**Objective:** The limb-girdle muscular dystrophies (LGMD) are a diverse group of disorders caused by mutations in different genes. Infrequently, some cases may show superimposed inflammatory changes, e.g. cases of dysferlinopathy, resulting in diagnostic confusion.

**Method:** We report a case of genetically confirmed calpainopathy masquerading as an immune-mediated necrotizing myopathy in a 7-year-old girl and highlight the diagnostic dilemma.

**Result:** Physical examination revealed only mild proximal weakness. Serological tests showed a markedly elevated creatine kinase, a positive anti-MDA5, anti-nuclear antibody of 1:80 and a negative anti-HMGCR. Muscle biopsy revealed patterns suggestive of necrotizing myopathy with some lymphocytic and eosinophilic infiltrates. Notably, MHC1 was diffusely upregulated. Endomysial fibrosis or fatty infiltration was not identified. The patient was treated with immunosuppressant therapy but with minimal transient response after 12 months. Genetic testing for muscular dystrophies later revealed 2 pathogenic variants in CAPN3, clinching the diagnosis of calpainopathy.

**Conclusion:** Calpainopathy can rarely show pronounced necrotizing features or even diffuse MHC1 upregulation on muscle biopsy, mimicking an immune-mediated necrotizing myopathy. Re-evaluation of a patient who does not respond as expected to immunomodulatory therapy is vital, even in the presence of myositis-specific antibodies. In our patient, genetic studies allowed for definitive diagnosis prior to the onset of symptoms of the dystrophy and also precluded the need for a repeat biopsy.

P66

Chronic disease course and IVIg-dependance in long-term follow-up of anti-HMGCR immune-mediated necrotizing myopathy

Océane Landon-Cardinal, Kuberaka Mariampillai, Céline Anquetil, Aude Rigolet, Baptiste Hervier, Nicolas Champtiaux, Olivier Benveniste, Yves Allenbach

Pitié-Salpêtrière University Hospital, Paris, France

**Correspondence:** Océane Landon-Cardinal

BMC Rheumatology 2019, 3(Suppl 1):P66

**Objectives:** Anti-HMGCR antibodies have been associated with a severe form of immune-mediated necrotizing myopathy (IMNM) with a poor muscle strength recovery and early muscle damage. These patients tend to require aggressive immunosuppressive therapy and present relapsing disease course. Our objective was to evaluate real-life treatment strategies in anti-HMGCR IMNM patients.

**Methods:** This monocentric study included all patients with anti-HMGCR IMNM with at least 12 months of follow-up. Medical records were retrospectively reviewed to assess clinical features at diagnosis, HLA typing, treatment strategies over the follow-up period (including corticosteroid (CS) use, number of immunosuppressive (IS) agent and intravenous immunoglobulin (IVIg) duration), disease course, and clinical status and therapeutic profile at last follow-up. Remission was defined as the presence of CK level ≤ 2 times the upper limit of normal associated with a stable manual muscle testing for ≥3 months. Quantitative variables are reported as median [IQR1-IQR3].

**Results:** Thirty-five patients were included. Age at diagnosis was 47.1 [26.1-60.2] years, 74% of patients were female, 29% were statin-exposed, all patients presented with muscle weakness (deltoid and psoas MRC-5 was 4.0 [2-4] and 4.0 [3-4], respectively) and highest CK level was 8146 [5000-12090] IU/L. Time from symptoms onset to treatment initiation was 0.8 [0.3-4.7] years. During the follow-up period, 91% of patients were treated with CS in combination with an IS agent, the majority of patients received IVIg (91%) and the number of treatment intensification was 2 [1-4]. Fourty percent of patients also received plasma exchanges as part of induction therapy. All patients demonstrated a chronic disease course and no patients were in treatment-free remission at last follow-up after 4.9 [3.1-8.9] years. At last follow-up, 60% of patients were in remission - most of which with IVIg (71%) -, 57% of patients were still receiving CS and CS dose was 8 [5-10] mg/day and 54% of patients had an IS agent. At last follow-up, only 40% of patients had a normal muscle strength, deltoid and psoas MRC-5 was 5 [4-5] and 4 [3-5], respectively, and CK level was 299 [200-559] IU/L. No predictors of remission or IVIg use

at last follow-up were identified, including demographic features, HLA-DRB1*11:01 and HLA-DRB1*07:01 status, muscle disease severity at onset and statin use. Therapy-related side effects were reported in 26% of patients.

**Conclusion:** In our population, anti-HMGCR IMNM was associated with a chronic disease course associated with IVIg-dependance.

P67

Clinical and histological features of necrotising myopathy: a prospective multi-centre Australian cohort study

Jessica Day, Sophia Otto, Kathy Cash, Vidya Limaye
University of South Australia, Adelaide, Australia

**Correspondence:** Jessica Day

BMC Rheumatology 2019, 3(Suppl 1):P67

**Background/Purpose:** Differentiation of necrotising myopathy (NM) from other forms of idiopathic inflammatory myopathy (IIM) has important therapeutic implications. Herein we describe the demographic, clinical and histological features of a consecutive cohort of NM patients in order to define the spectrum of disease, characterise the features that distinguish NM from other IIM subtypes and identify distinct phenotypes of NM.

**Methods:** Muscle samples and clinical details were prospectively collected from patients with NM (n = 63), other forms of IIM (n = 45) and controls (n = 17). Consecutive muscle sections were stained using immunohistochemistry and graded by a muscle pathologist. Clinical and histological subgroups of NM were defined and compared.

**Results:** NM patients displayed marked clinical, biochemical and histological heterogeneity. Twenty-four percent (15/63) demonstrated widespread muscle necrosis, with the remainder exhibiting only mild (23/63, 37%) or moderate (25/63, 40%) necrosis. There was notable variability in creatine phosphokinase (CK) levels (range: 23 - 219000 IU/L) and muscle strength. Patients of Aboriginal and Torres Strait Islander heritage appear to suffer a severe form of the disease. Sarcolemmal and sarcoplasmic complement deposition was common and correlated with the degree of necrosis and clinical severity. Those who were seropositive for myositis-specific autoantibodies (MSAs) featured higher capillary complement deposition (p = 0.02) and more widespread sarcolemmal MHC I expression (p = 0.04) compared with seronegative patients.

**Conclusions:** We found NM to be a markedly heterogeneous condition histologically, and identified certain clinical and histological features which are associated with severe forms of the disease. In addition, we identified capillary complement deposition and widespread MHC I deposition to be associated with features of systemic immune activation; routine evaluation for these could have diagnostic and therapeutic utility.

P68

Tocilizumab Improve Muscle Strength in Patients with Refractory Anti-Signal Recognition Particle and Anti-3-Hydroxy-3-Methylglutaryl-CoA Reductase Myopathies

Sizhao Li, Wenli Li, Wei Jiang, Linrong He, Xia Liu, Xiaoming Shu, Qinglin Peng, Li Ma, Guochun Wang, Xin Lu
China-Japan Friendship Hospital, Beijing, China

**Correspondence:** Sizhao Li

BMC Rheumatology 2019, 3(Suppl 1):P68

**Objective:** This study aimed to assess the clinical response of tocilizumab (TCZ), a humanized anti-interleukin-6 (IL-6) receptor monoclonal antibody, in a series of patients with refractory anti-signal recognition particle (SRP) and anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) myopathies and explored the role of IL-6 in muscle weakness.

**Methods:** The clinical, laboratory, and histopathological data of 11 patients with refractory anti-SRP and anti-HMGCR myopathies treated with TCZ were analyzed. The clinical response was assessed by the changes in Manual Muscle Testing 8 (MMT-8) scores and serum creatine kinase (CK) levels. Serial muscle biopsies were conducted to compare the changes in muscular pathology.
Results: After 3–7 rounds of TCZ, the mean dosage of adjunctive prednisone was reduced from 36.8 to 11.8 mg/day. Nonetheless, the MMT-8 score increased from 42.2 (±4.5) to 75.9 (±5.9) and all patients achieved more than 50% improvement in the MMT-8 score. The serum CK decreased from 3105.9 (±2555.8) to 614.1 (±681.3) IU/L and all patients achieved more than 25% improvement in serum CK levels. Before TCZ treatment, the muscle samples showed local expression of IL-6 around infiltrating macrophages, prominent regeneration (25.7% ± 14.8%, n = 9), and high levels of atrophy factor (562.7±146.2, n = 9). After TCZ treatment, the levels of atrophy factor markedly reduced from 535.2 ± 171.9 to 75.4 ± 68.6 (n = 5), and the impaired regeneration substantially improved.

Conclusions: TCZ is a promising therapeutic agent for refractory anti-SRP and anti-HMGCR myopathies. It recovers muscle regeneration and improves muscle strength.

## P69
### Clinical Characteristics of Immune-Mediated Necrotizing Myopathies: A Retrospective Study in a Single-center Muscle Biopsy Cohort

Hongxia Yang, Xiaolan Tian, Hanbo Yang, Yamei Zhang, Xiaoming Shu, Guochun Wang, Xin Lu
China Japan Friendship Hospital, Beijing, China

Correspondence: Hongxia Yang; Xin Lu

BMC Rheumatology 2019, **3**(Suppl 1):P69

**Objective:** Immune-mediated necrotizing myopathies(IMNM) is recently entitled a novel subset of idiopathic inflammatory myopathies(IIM) which patients has predominant muscle weakness and are resistant to conventional therapy. The aim of this study was to investigate the frequency and characteristics of patients with IMNM in our single-center muscle biopsy cohort.

**Methods:** A total of 512 patients who were admitted to our hospital for muscle biopsy due to muscle weakness or elevated serum level of creatine kinase (CK) from May 2008 to December 2017 were involved in this study. All clinical data including demographic information, clinical manifestations, laboratory tests, the reports of muscle biopsy were collected retrospectively from the record of Hospital Information System. The diagnosis of IMNM was according to 2004 the European Neuromuscular Centre criteria for pathological features of muscle biopsy of IMNM or patients with anti-SRP or anti-HMGCR autoantibodies.

**Results:** Of 512 patients in our cohort, 71 of patients (13.8%) were diagnosed as IMNM and 39 of patients were polymyositis (PM) (7.6%). Of 253 patients (49.4%) were definitely diagnosed as non-IIM such as muscular dystrophy(MD) (11.9%), asymptomatic hyperCKemia (9.1%), lipid storage disease(LSD) (3.1%), neurogenic myopathy (3.7%), infection-related myopathies (2.7%), endocrine myopathies (2.5%) and other connective tissue disease accompanied muscle symptom (12.1%). Of 13 patients (2.5%) were diagnosed as certain disease unrelated to muscular disorders. Of 63 cases (12.3%) cannot be diagnosed as definite disease. Compared the characteristics of IMNM with PM, MD and LSD in our cohort, which those patients had similar manifestations of muscle weakness and high CK level, the age of onset of patients with IMNM and PM were older than those with MD and LSD (IMNM vs PM, MD and LSD: 41.63 vs 40.14, 24.72 and 24.69, p < 0.001). IMNM patients had more manifestation of upper limb weakness (56.3%), while LSD patients more frequently presented lower limb weakness (75%). Patients with IMNM had more frequent manifestations of rash (23.9%), interstitial lung disease (31%) and dysphagia (36.6%) compare to patients with PM, MD and LSD. Patients with MD had the highest CK level (3324.50 ± 874.25), however patients with PM had the lowest CK level (450.50 ± 121.25), there were statistical significant difference of CK level among the four groups (p < 0.001).

**Conclusions:** IMNM is the most common subset in the patients with muscle weakness and high CK level in our single-center muscle biopsy cohort, which should be differentiated from PM, MD and LSD.

## P70
### The role of dysfunctional T-cells in immune mediated myositis

Samuel Knauss¹, Corinna Preuße¹, Yves Allenbach², Sarah Leonard-Louis², Mehdi Touat², Norina Fischer¹, Helena Radbruch¹, Ronja Mothes¹, Vitaly Matyash¹, Wolfgang Boehmerle¹, Matthias Endres¹, Hans-Hilmer Goebel¹, Olivier Benveniste², Werner Stenzel¹

¹Charité Universitätsmedizin Berlin, Berlin, Germany; ²Pitié-Salpêtrière University Hospital, Paris, France

Correspondence: Samuel Knauss

BMC Rheumatology 2019, **3**(Suppl 1):P70

**Objective:** The objective of the present study was to investigate the presence of T cells exhibiting dysfunctional phenotypes in immune-mediated myopathies. To this effect we analysed T cell exhaustion and senescence markers, in skeletal muscle biopsies from patients with IMNM, sIBM and myositis induced by immune checkpoint inhibitors (irMyositis).

**Methods:** We analysed skeletal muscle biopsies from 12 IMNM, seven sIBM and eight irMyositis patients using immunostaining and immunofluorescence as well as by qPCR. Eight biopsies from non-disease subjects and six biopsies from patients with Duchenne muscular dystrophy served as controls.

**Results:** In double-immunostainings of biopsies from IMNM, sIBM and irMyositis patients, CD3+CD8+ T cells were largely PD1-positive, while CD68+ macrophages were sparsely PD-L1-positive. PD-L2 was strongly expressed on the sarcolemma of myofibers and co-localised with MHC class I. CD68+ macrophages co-localised with PD-L2. In qPCR analyses we found a strong signal of senescent T cells in skeletal muscle of sIBM, revealing a distinct immunological signature. Biopsies from patients with irMyositis showed mild signs of senescence and exhaustion. Of note, biopsies from Duchenne boys did not exhibit any molecular signs of senescence or exhaustion.

**Conclusion:** We found evidence of T cells expressing markers of exhaustion and senescence in IMNM, sIBM and irMyositis. Activation of the pathways involving the programmed cell death protein 1 (PD1) receptor and its cognate ligands PD-L1/PD-L2 have been linked to a persistent exposure of antigens. To our knowledge, this data is the first evidence of presence of dysfunctional T cells in IMNM, sIBM and irMyositis. These findings may guide the way to a novel understanding of the immune pathogenesis of immune-mediated myopathies.

## P71
### Use of Protein Convertase Subtilisin/Kexin Type 9 (PCSK9) inhibitors in statin-associated autoimmune myopathy; a case-series

Eleni Tiniakou¹; Andrew Mammen²; Lisa Christopher-Stine¹

¹Johns Hopkins University School of Medicine, Baltimore, USA; ²National Institute of Health, Bethesda, USA

Correspondence: Eleni Tiniakou

BMC Rheumatology 2019, **3**(Suppl 1):P71

**Objective:** Statin-triggered immune mediated necrotizing myopathy (IMNM) is associated with autoantibodies against HMGCR, the pharmacologic target of statins. Re-introduction of statins is avoided or suboptimal dosing is attempted with careful monitoring. As these patients commonly have a high cardiovascular (CV) risk, physicians face a conundrum as the recommendations for a lipid-lowering diet can only achieve minimal results. The introduction though of PCSK9 inhibitors not only promoted a more effective cholesterol control, but also raised the question of their safety in patients with anti-HMGCR IMNM.

**Methods:** Amongst 122 anti-HMGCR+ myositis patient evaluated at the Johns Hopkins Myositis Center, we identified nine patients with severe CV disease and/or diabetes who were placed on a therapeutic trial with PCSK9 inhibitors.

**Results:** The mean age at initiation of PCSK9 inhibitors was 69.75 years and the mean duration of anti-HMGCR myositis was 7 years (SD 5.73 years). Six patients were placed on evolocumab and three on alirocumab. The average duration of follow-up on PCSK9 inhibitors was 19 years.
months (2-31 months). For two of the patients, the initiation of PCSK9 inhibitors was concurrent with changes in their immunosuppressive treatments, while the rest were clinically stable. The mean CK level prior to the initiation of PCSK9 inhibitors was 943±1135 IU per liter and at the following visit it was slightly reduced to 810±1142. The mean CK at the most recent evaluation was substantially lower at 395±391, which is attributed to intense immunosuppressive treatment of the two active myositis patients. Parallel trend was observed for the titers of anti-HMGCR antibodies. Similarly, there was no decrease in the hip flexion and deltoid muscle strength during their follow up visits. Remarkably, two patients placed on PCSK9 inhibitors exhibited improvement of their CPK and muscle strength without the addition of immunosuppression.

**Conclusion:** The exact pathogenesis of anti-HMGCR IMNM and the link with statins remain unknown. Statin-induced overexpression of HMGCR in muscle tissue and/or statin binding to HMGCR potentially revealing cryptic epitopes could lead to initiation and propagation of an autoimmune response. Therefore, statins are avoided in these patients. However, we cannot dismiss an association with different steps of the cholesterol pathway, and therefore, we could not exclude similar interaction with PCSK9 inhibitors. We present nine patients with severe CV risk who were able to tolerate PCSK9 inhibitors without exacerbation of underlying myopathy. Thus, our experience to date suggests that PCSK9 inhibitors are safe in anti-HMGCR IMNM patients with high CV risk.

## P72

### Clinical presentation and outcome in anti-SRP IMNM: french cohort of 54 patients

Marion Peyre, Nicolas Champtiaux, Kuberaka Mariampillai, Océane Landon-Cardinal, Mathieu Vautier, Baptiste Hervier, Perrine Guillaume-Jugnot, Aude Rigolet, Yves Allenbach, Olivier Benveniste Hôpital Pitié Salpetrière, Paris, France

**Correspondence:** Marion Peyre

BMC Rheumatology 2019, 3(Suppl 1):P72

**Objective:** Anti-SRP Immune-Mediated Necrotizing Myopathies (IMNM) were identified in 2004, and represent a rare cause of autoimmune myopathy, with a particularly brutal presentation and high CPK level. Clinical characteristics of anti-SRP myopathies are now well described. Thus, their evolutive profil is less studied.

**Method:** We report a retrospective cohort of 54 adult patients with anti-SRP necrotizing myopathy, based upon a review of every successive patient with anti-SRP admitted in our tertiary center since 2000.

**Results:** Fifty-four patients were included (sex ratio M/F: 0,4), and we disposed of follow-up datas for 42 of them. Mean age at symptoms was 44 years old. First signs were myalgias (61%), amyotrophia (48%), and muscular impairment. Mean MMT8 score was 109 (for a maximal score of 150 points), and seven patients had a MMT8 < 80. Fourty-eight percent of patients presented swallowing disorders. Seventeen patients (31%) had cardiac involvement at MRI, and 27 (50%) had pulmonary involvement. Notably we observed that black patients tended to have a more rapid onset of disease (time between first symptoms and the diagnosis: 4 +/- SD months) compare to the other patients (vs 18+/- months; p=0,08) and the CPK level was higher (12.558UI/L vs 7.130UI/L, p=0,008). Patients received an average number of 2,4 disease-modifying antirheumatic drugs (DMARDs). All patients but one received corticosteroids, and 35% encountered severe adverse events. Methotrexate, Azathioprine and Rituximab were given to respectively 79%, 46% and 31 patients. Fourty-five patients (83%) received at least one perfusion of IVlg. Mean follow-up duration was 86 +/- SD months after diagnosis. Seventeen patients (40%) only recovered a normal muscular function, and twenty three

(54%) had low disabily attested by a Rankin scale < 2. Thirty-five percent of patients still have an active disease at the end of the follow-up, defined by either CPK rate higher than 3N or clinical progression. Black patients had more refractory disease (10/14 patients still have active disease, vs 5/25 in Caucasian patients, p=0,004). Thirty-four patients were still treated with corticosteroids at the end of the follow-up.

**Conclusion:** This cohort is, to our knowledge, the biggest in Europe. Our results are consistent with literature, except that we found higher rate of pulmonary and cardiac involvement. Originally, a new pattern is described here, with a more severe and more refractory disease in black patients.

## P73

### Anti-HMGCR antibodies as a biomarker for immune-mediated necrotizing myopathies: Experience from a large single center study

Maryam Dastmalchi¹, Simone Barsotti², Andrew Mammen³, Katherine Pak⁴, Karina Gheorghe¹, Ingrid Lundberg¹

¹Karolinska University Hospital, Stockholm, Sweden; ²University of Pisa, Pisa, Italy; ³National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, USA

**Correspondence:** Maryam Dastmalchi

BMC Rheumatology 2019, 3(Suppl 1):P73

**Objectives:** The immune-mediated necrotizing myopathies (IMNMs) are a group of acquired autoimmune muscle disorders characterized by proximal muscle weakness, high levels of creatinine kinase (CK), and infrequent extra-muscular involvement. Muscle biopsies in IMNM differ from other subgroups of idiopathic inflammatory myopathies (IIM) by the presence of myofiber necrosis and prominent regeneration without focal endomysial collections lymphocytic inflammatory infiltrates. Perifascicular atrophy has been reported in 20% of patients. Anti-HMGCR myopathy is a form of IMNM traditionally associated with statin exposure and may be resistant to standard immunosuppressive agents, particularly among younger statin-naïve patients.

**Methods:** Patients with IIM were identified in the SweMyoNet registry between 1988 and 2014 and classified according to 2017 EULAR/ACR criteria. The first available serum sample was analyzed for anti-HMGCR autoantibodies by ELISA. Positive sera were confirmed by immunoprecipitation. Clinical data were extracted from SweMyoNet or medical records. Demographic data, statins exposure status, disease activity at presentation and at last follow up, and muscle biopsy features were compared between HMGCR+ and HMGCR- groups. Comparisons between groups were evaluated using non-parametric statistical tests (Mann-Whitney).

**Results:** 312 patients were included, and 13 (4.16%) were anti-HMGCR+. Women accounted for 12 (92.3%) of HMGCR+ individuals and 182 (60.9% p = 0.021) of anti-HMGCR- patients. Age at onset was 70.5 for HMGCR+ and 67.2 for HMGCR-, NS. None of the anti-HMGCR+ patients had been exposed to statins. There was no difference between the anti-HMGCR+ and negative group concerning age at disease onset, sub-diagnosis of IIM, extra-muscular involvement such as heart/skin involvement or ILD, muscle function measured by MMT8 and HAQ or serum levels of CK. At last evaluation, the anti-HMGCR+ patients had higher serum CK levels without other differences in outcome measures. There was no difference in the use of disease modifying drugs or biologic agents between the two groups except for IVlg, which was more often used in HMGCR+ patients p < 0.041. The prevalence of coexisting myositis-specific or myositis-associated autoantibodies was not significantly different between anti-HMGCR+ and anti-HMGCR- groups. We found a tendency towards increased presence of Ro52 antibodies in the HMGCR- group. In muscle biopsies, perifascicular atrophy was presented in 40% in the HMGCR+ group and 13.4% in HMGCR- group p = 0.041.
Conclusion: In this cohort of Swedish IIM patients, the prevalence of anti-HMGCR autoantibodies was low (4.1%) and all were statin naive. The high frequency of perifascicular atrophy in muscle biopsies was surprising and requires further evaluation.

## P74
### Anti-RNP antibodies delineate a subgroup of necrotizing myositis

Nadège Wesner, Akinori Uruha, Shigeaki Suzuki, Kuberaka Mariampillai, Benjamin Granger, Nicolas Champtiaux, Aude Rigolet, Yoland Schoindre, Sylvain Le Jeune, Perrine Guillaume-Jugnot, Mathieu Vautier, Baptiste Hervier, Anne Simon, Francoise Granier, Laure Gallay, Ichizo Nishino, Olivier Benveniste, Yves Allenbach

BMC Rheumatology 2019, **3**(Suppl 1):P74

**Objectives:** Myositis can occur as a specific entity or as a part of a spectrum of non-specific connective tissue disorders. Myositis-specific antibodies are known to delineate subgroups of myositis; however, the ability of myositis-associated antibodies to isolate homogeneous groups of patients remains unknown. Anti-U1 small nuclear ribonucleoprotein particle (RNP) antibodies are among the most prevalent myositis-associated antibodies. It may also be detected in mixed connective tissue disease, systemic lupus erythematosus, systemic sclerosis or Sjögren's syndrome without myositis. We aimed to describe the clinical and pathological myositis phenotypes associated with this particular auto-antibody, and to compare them to myositis patients without anti-RNP antibodies.

**Methods:** In this international multicentric (France and Japan) retrospective study, myositis patients with anti-RNP antibodies with positive RNA immunoprecipitation were enrolled and compared to a cohort of myositis patients without anti-RNP antibodies. Clinical and pathological data were analysed. Unsupervised descriptive methods were used to compare patients.

**Results:** Unsupervised hierarchical cluster analysis of the global cohort including anti-RNP- myositis (n=208) identified four clusters. One cluster corresponded to the anti-RNP patients: indeed, 70% of patients with anti-RNP antibody were in this cluster and presented the classical anti-RNP+ phenotype. The three others clusters corresponded to well-known myositis entities: immune-mediated necrotizing myopathies, anti-synthetase syndrome with anti-Jo1 antibodies and dermatomyositis. Anti-RNP+ patients (n=46) were characterized by severe necrotizing myositis associated with frequent extra-muscular manifestations, including Raynaud phenomenon and/or puffy hands, arthralgia and/or interstitial lung disease. Only, twelve anti-RNP+ patients were also positive for myositis-specific antibodies. Patients' outcome was characterized by a frequent therapeutic intensification (14/20, 70%), a frequent remission rate (14/20, 70%) but also by remaining muscle damage for 20% of patients (4/20).

**Conclusion:** Anti-RNP+ myositis display characteristic muscular and extra-muscular phenotype, distinct from anti-RNP- myositis. This leads to distinction of anti-RNP+ myositis as a particular subgroup of idiopathic inflammatory myopathies.

## P75
### Myositis autoantigen expression correlates with muscle regeneration but not autoantibody specificity

Iago Pinal-Fernandez<fnref n="1" />, David R. Amici<fnref n="1" />, Cassie Parks<fnref n="1" />, Assia Derfoul<fnref n="1" />, Maria Casal Dominguez<fnref n="1" />, Katherine Pak<fnref n="1" />, Richard Yeker<fnref n="1" />, Paul Plotz<fnref n="1" />, Jose C. Milisenda², Josep M. Grau-Junyent², Albert Selva-O'Callaghan³, Julie Paik⁴, Jemima Albayda⁴, Andrea Corse⁴, Tom Lloyd⁴, Lisa Christopher-Stine⁴, Andrew Mammen<fnref n="1" />

**Correspondence:** Iago Pinal-Fernandez

BMC Rheumatology 2019, **3**(Suppl 1):P75

**Objectives:** Although more than a dozen myositis-specific autoantibodies (MSAs) have been identified, most myositis patients produce a single MSA. The specific overexpression of a given myositis autoantigen

in myositis muscle has been proposed to initiate and/or propagate autoimmunity against that autoantigen. To test this hypothesis, we quantified autoantigen RNA expression in myositis muscle biopsies, regenerating mouse muscles, and cultured human muscle cells.

**Methods:** RNA-sequencing was performed on biopsies from MSA-positive myositis patients, regenerating mouse muscles, and cultured human muscle cells.

**Results:** Muscle biopsies were available from 106 patients with autoantibodies recognizing HMGCR, SRP, Jo1, NXP2, Mi2, TIF1γ, or MDA5. The increased expression of a given autoantigen in myositis muscle was not associated with autoantibodies recognizing that autoantigen. In both myositis muscle biopsies and regenerating mouse muscles, myositis autoantigen expression correlated directly with the expression of markers of muscle regeneration and inversely with the expression of genes encoding mature muscle proteins. Myositis autoantigens were also expressed at high levels in cultured human muscle cells.

**Conclusions:** Most myositis autoantigens are highly expressed during muscle regeneration, which may relate to the propagation of autoimmunity. However, factors other than specific autoantigen overexpression are likely to govern the development of unique autoantibodies in individual patients.

## P76
### Aberrant expression of 'High Mobility Group Box Protein 1" (HMGB1) in the idiopathic inflammatory myopathies

Jessica Day, Sophia Otto, Kathy Cash, Preethi Eldi, Susanna Proudman, Pravin Hissaria, John Hayball, Vidya Limaye
University of South Australia, Adelaide, Australia

**Correspondence:** Jessica Day

BMC Rheumatology 2019, **3**(Suppl 1):P76

**Objectives:** High Mobility Group Box Protein 1 (HMGB1), is a ubiquitous nuclear DNA-binding protein that can translocate to the cytoplasm and extracellular space, where it exerts pro-inflammatory or pro-repair effects depending on its molecular state and the surrounding cytokine milieu. Herein, we evaluate expression of HMGB1 in different forms of IIM and correlate it with other intramuscular histological processes to determine the role(s) of this complex protein in these conditions.

**Methods:** Consecutive muscle sections were obtained from 132 IIM patients with necrotising myopathy (NM, n = 59), dermatomyositis (DM, n = 17), polymyositis (PM, n = 19), inclusion body myositis (IBM, n = 22) and non-specific IIM (NSIIM, n = 15) in addition to 18 control samples. Sections were stained for HMGB1, CD68 (macrophages), CD45 (lymphocytes), neonatal myosin heavy chain (nMHC, regenerating myofibres) and LC3 (an autophagic protein) using immunohistochemistry. Slides were independently graded by a muscle pathologist.

**Results:** Muscle samples from 132 IIM patients with necrotising myopathy (NM, n = 59), dermatomyositis (DM, n = 17), polymyositis (PM, n = 19), inclusion body myositis (IBM, n = 22) and non-specific IIM (NSIIM, n = 15) were analysed, in addition to 18 control samples. Sarcoplasmic HMGB1 was significantly elevated in all IIM subtypes compared with controls (p < 0.001). Structures exhibiting aberrant HMGB1 expression included: infiltrating immune cells, necrotic myofibres, regenerating myocytes and myofibres exhibiting autophagic or mitochondrial dysfunction. Patients with NM and IBM had significantly increased sarcoplasmic HMGB1 compared with DM, PM and NSIIM. In NM, HMGB1 grades highly correlated with the degree of necrosis (Rs 0.74, p < 0.001) and inflammation (CD68: Rs 0.66, p < 0.001; CD45: Rs 0.62, p < 0.001). In IBM, HMGB1 grades highly correlated with regenerating myofibers (Rs 0.81, p < 0.001) and autophagic proteins (Rs 0.85, p = 0.002).

**Conclusion:** Aberrant sarcoplasmic HMGB1 expression was observed in all forms of IIM, but a notably elevated levels were detected in NM and IBM. Overall, HMGB1 correlated with a number of inflammatory, metabolic, regenerative and destructive processes in the muscle microenvironment, suggesting it plays a complex and multi-faceted role in the pathophysiology of autoimmune muscle disease. The relative balance of these processes within an IIM patient may explain the

<footnote n="1">¹National Institutes of Health, Bethesda, USA; ²Clinic Hospital, Barcelona, Spain; ³Valle de Hebron, Barcelona, Spain; ⁴Johns Hopkins University, Baltimore, USA</footnote>
varying degrees of sarcoplasmic HMGB1 staining we observed across subtypes. Understanding how HMGB1 contributes to the pathogenesis of these complex conditions may lead to novel diagnostic paradigms and therapeutic interventions.

P77

Identification of heat shock factor 1 (HSF1) as a novel autoantigen in idiopathic inflammatory myopathy

Yamei Zhang, Qing-Lin Peng, Han-Bo Yang, Jing-Li Shi, He Chen, Xin Lu, Guochun Wang
China-Japan Friendship Hospital, Beijing, China

**Correspondence:** Yamei Zhang

BMC Rheumatology 2019, **3**(Suppl 1):P77

**Objectives:** Antibodies in idiopathic inflammatory myopathy (IIM) were useful for clinical diagnosis and prognostication. We previously identified a novel antibody against heat shock factor 1 (HSF1) in IIM patients, and our study aimed to evaluate disease specificity and clinical significance of it.

**Methods:** Anti-HSF1 was assayed by ELISA using serum from patients with IIM (n=613), Sjogren's syndrome (SS, n=40), systemic lupus erythematosus (SLE, n=40), rheumatoid arthritis (RA, n=37) and healthy controls (HC, n=65), and validated by immunoblotting and dot blotting. Immunofluorescence staining was used to detect the expression of HSF1 in IIM patients muscle tissues and C2C12 cells.

**Results:** Anti-HSF1 could be detected in 65/612 (10.6%) IIM, 4/37 (10.8%) RA, 5/40 (12.5%) SS, 2/40 (5%) SLE and 2/65 (3.1%) HCs. Subgroup analyses in IIM patients revealed that anti-HSF1 was present in 56/489 (11.5%) of DM, 8/112 (7.1%) of PM and 1/11 (9.1%) of myositis-overlap syndrome. Anti-HSF1+ IIM patients had a higher prevalence of TIF1γ positivity (P=0.046), hypergammaglobulinemia (P < 0.001), elevated C-reactive protein (CRP, P=0.039) and erythrocyte sedimentation rate (ESR, P=0.006). Moreover, anti-HSF1 was found associated with higher incidence of malignancy (P=0.008), and intriguingly we found no detectable anti-HSF1 in 27 cancer patients. In addition, multivariate analysis confirmed that anti-HSF1 was associated with an increased risk of malignancy (OR 2.4 [95%CI 1.0-5.9], P= 0.05). Cross-sectional study in 226 IIM patients without malignancy found that anti-HSF1+ patients (n=51) had higher PGA VAS (P=0.014) than anti-HSF1- patients (n=175), and anti-HSF1 levels in anti-HSF1+ patients were positively correlated with PGA VAS (r=0.325, P=0.02), constitutional VAS (r=0.312, P=0.026), muscle VAS (r=0.399, P=0.004) and LDH levels (r=0.405, P=0.003). In the longitudinal study involving 10 anti-HSF1+ IIM patients without malignancy, generalized estimating equation (GEE) model confirmed that anti-HSF1 levels were positively correlated with PGA (physician global assessment) VAS (β=2.9, P=0.001), muscle VAS (β=4.3, P < 0.001) and pulmonary VAS (β=4.7, P < 0.001). Furthermore, we found HSF1 protein co-expressed with neural cell adhesion molecule (NCAM) in muscle biopsy specimens of IIM patients. By analyzing the expression of HSF1 protein in different stage of cultured muscle cells, we found HSF1 was expressed by differentiating muscle cells, while no HSF1 expression was observed in myoblasts.

**Conclusions:** Anti-HSF1 was associated with malignancy and disease activity in IIM, and its target represented a novel autoantigen in IIM.

P78

Investigating the Specificity of the Myositis Profile-4 EUROLINE assay

Clara Ventin-Rodriguez¹, James B. Lilleker², Shuayb Elkhalifa², Hector Chinoy²

¹Complejo Hospitalario Universitario de A Coruña, A Coruna, Spain; ²The University of Manchester, Manchester, UK

**Correspondence:** Clara Ventin-Rodriguez; James B. Lilleker

BMC Rheumatology 2019, **3**(Suppl 1):P78

**OBJECTIVES:** The Myositis Profile 4 EUROLINE immunoblot includes 16 myositis-related autoantibodies (Mi2-alpha, Mi2-beta, TIF1-gamma, MDA5, NXP2, SAE1, KU, PM-Scl75, PM-Scl100, Jo1, SRP, PL-7, PL-12, EJ, OJ,

Ro52) and is increasingly used in patients with suspected idiopathic inflammatory myopathy (IIM). Sensitivity is thought to be high, but concerns have been raised about low specificity. We investigated the sensitivity and specificity of antibody positivity for IIM and studied factors associated with true and false positivity.

**METHODS:** All patients between January of 2016 and July 2018 whom where testing using the Myositis Profile 4 EUROLINE immunoblot were identified. Assay results were matched with clinical data (highest creatine kinase (CK) level, electromyogram, muscle biopsy, pre-test working diagnosis and final diagnosis) collected retrospectively. For patients with suspected IIM, we also calculated the classification probability according to EULAR/ACR criteria.

**RESULTS:** Of 401 identified patients, clinical data was available for 349. 65% (226/349) were female and the mean age was 54 years (SD 14). Overall, the assay found strong and weak antibody positivity for 23% (79/349) and 19% (66/349) of patients respectively. Pre-test working diagnoses were categorised as IIM (27% 94/349), other connective tissue diseases (CTDs) without suspected muscle involvement (40% 139/349) and myopathic syndromes with low probability of IIM (33%, 116/349). The likelihood of any strong positive result was highest for those with suspected IIM (38% versus 21% and 12% respectively, p< 0.001). Weak positivity was found at a similar rate across the three groups (20%, 20% and 16% respectively, p=0.709). The false positive rate for strong positivity was 15% (40/266). The rate of false positivity was highest for those with a pre-test working diagnosis of other CTDs (20% 28/137) and myopathic syndromes with low probability of IIM (10% 11/110), compared to the suspected IIM group (5% 1/19). Sensitivity and specificity for IIM of any strong antibody positivity was 47% and 85% respectively. Only a pre-test working diagnosis of IIM was associated with increased likelihood of strong antibody positivity (46% (36/79) for the strong positive groups versus 22% (58/270) in the negative group, OR 3.1 (95%CI 1.80-5.20, p< 0.001)), with no associations demonstrated for age, gender, myopathic electromyogram, CK level or inflammatory muscle biopsy.

**CONCLUSION:** In our cohort, immunoblot testing sensitivity for IIM was moderate and specificity was high. However, false positive results were common, especially in those where the pre-test probability of IIM was low, potentially leasing to unnecessary further investigation in such cases.

P79

MicroRNA and mRNA profiling in the idiopathic inflammatory myopathies

Joanna E. Parkes, Anastasia Thoma, Adam Lightfoot, Philip J. Day, Hector Chinoy, Janine A. Lamb
University of Manchester, Manchester, UK

**Correspondence:** Joanna E. Parkes

BMC Rheumatology 2019, **3**(Suppl 1):P79

**Objectives:** The idiopathic inflammatory myopathies (IIMs) are heterogeneous autoimmune conditions of skeletal muscle inflammation and weakness. MicroRNAs (miRNAs) are short, non-coding RNA which regulate gene expression of target mRNAs. The aim of this study was to profile miRNA and mRNA in IIM and identify miRNA-mRNA relationships which may be relevant to disease.

**Methods:** mRNA and miRNA in whole blood samples from 7 polymyositis (PM), 7 dermatomyositis (DM), 5 inclusion body myositis (IBM) and 5 non-myositis controls was profiled using next generation RNA sequencing. Gene ontology and pathway analyses were performed using GOseq and Ingenuity Pathway Analysis. Dysregulation of miRNAs and opposite dysregulation of predicted target mRNAs in IIM subgroups was validated using RTqPCR and investigated by transfecting human skeletal muscle cells with miRNA mimic.

**Results:** Overall, 129, 53 and 24 differentially expressed mRNAs were identified for PM, DM and IBM compared to controls, respectively (false discovery rate < 0.05). Analysis of the 5 anti-Jo1 positive samples (4 PM and 1 DM) compared to controls identified 691 differentially expressed genes. In analysis of miRNAs, 4, 4, 7 and 3 miRNAs were significantly differentially expressed for the PM, DM, IBM and anti-Jo1 positive subgroups compared to controls, respectively (p <
0.01). Analysis of differentially expressed genes showed that interferon signalling and anti-viral response pathways were upregulated in PM and DM compared to controls. The anti-Jo1 autoantibody positive subset of PM and DM had more significant upregulation and predicted activation of interferon signalling and highlighted T-helper (Th1 and Th2) cell pathways. In miRNA profiling miR-96-5p was significantly upregulated in PM, DM and the anti-Jo1 positive subset. RTqPCR replicated miR-96-5p upregulation and predicted mRNA target (ADK, CD28 and SLC4A10) downregulation. Transfection of a human skeletal muscle cell line with miR-96-5p mimic resulted in significant downregulation of ADK.

**Conclusion:** MiRNA and mRNA profiling identified dysregulation of interferon signalling, anti-viral response and T-helper cell pathways, and indicates a possible role for miR-96-5p regulation of ADK in pathogenesis of IIM.

## P80

### Alterations in activin A-myostatin-follistatin system associate with disease activity in inflammatory myopathies

Lucia Vernerová, Veronika Horváthová, Tereza Kropáčková, Martina Vokurková, Martin Klein, Michal Tomčík, Sabína Oreská, Hana Štorkánová, Herman Mann, Olga Kryštúfková, Jiri Vencovský
Institute of Rheumatology, Prague, Czech Republic

**Correspondence:** Lucia Vernerová

BMC Rheumatology 2019, **3**(Suppl 1):P80

**Objectives:** The aim of this study was to investigate myokines involved in muscle atrophy, such as myostatin, follistatin and activin A, in idiopathic inflammatory myopathies (IIM). Recent findings show that rather than myostatin alone, the activin A-myostatin-follistatin system is believed to play an important role in musculoskeletal growth, development and aging. The myostatin biology known by now encourages considering its blocking therapy in IIM as the muscle weakness and atrophy persist in patients even after the suppression of inflammation.

**Methods:** A total of 94 patients with IIM and 155 healthy controls (HC) were enrolled in the study. Apart from serum samples taken during regular patients' visits, 20 IIM patients and 21 HC underwent a muscle biopsy. Circulating concentrations of myostatin, follistatin, activin A and TGF-β1 were assessed by ELISA. The expression of myokines and associated genes involved in myostatin signalling pathway in muscle tissue was determined by real-time PCR using TaqMan® Gene Expression Assays.

**Results:** We report decreased levels of circulating myostatin (2024±1111 vs. 2647±792 pg/ml; p=0.0003) and increased follistatin (1542±564 vs. 1332±670 pg/ml; p=0.008) in IIMs compared to HC. Activin A levels were also higher in IIM (394±142 vs. 334±132 pg/ml; p=0.013) compared to controls while no significant difference was observed for serum TGF-β1. Myostatin was negatively correlated to disease activity measures such as muscle disease activity (muscle DA) (r=-0.289, p=0.015) and manual muscle testing of 8 muscles (MMT8) (r=-0.366, p=0.002). On the other hand, follistatin correlated positively with muscle DA (r=0.235, p=0.047). Gene expression analysis showed higher follistatin (p=0.040) and myostatin inhibitor FSTL3 (p=0.008) levels and lower expression of activin receptor type 1B (ALK4) (p=0.034) and signal transducer SMAD3 (p=0.023) in IIM muscle tissue compared to controls.

**Conclusion:** The findings of this study contradict the expected pattern of activin A-myostatin-follistatin system in muscle wasting diseases by showing lower myostatin and higher follistatin in circulation and attenuated expression of myostatin pathway signalling components in skeletal muscle of patients with inflammatory myopathies. The activin A-myostatin-follistatin system is altered in myositis either to counterbalance the muscle wasting induced by inflammation, or on the other hand, as a result of prolonged inflammation.

## P81

### Differential immune response of skeletal muscle groups in idiopathic inflammatory myopathies

Alexander Michels

University Hospital Muenster, Münster, Germany

BMC Rheumatology 2019, **3**(Suppl 1):P81

**Objectives:** Idiopathic inflammatory myopathies (IIM) comprise a heterogenic group of immune-mediated diseases leading to progressive destruction of the muscle. IIM subtypes exhibit different patterns of affected muscle groups. In polymyositis, dermatomyositis and immune-mediated necrotizing myopathy proximal muscle groups are affected symmetrically. In contrast, inclusion body myositis is mainly characterized by asymmetric weakness of distal muscle groups. Interestingly, specific cytokine patterns can be found in the different IIM subtypes. In this study we aim to investigate whether differential immunological properties and responses of muscle and endothelial cells from distinct skeletal muscle groups underlie the observed patterns.

**Methods:** We isolated primary murine skeletal muscle (pmMCs) and microvascular endothelial (pmMMECs) cells from proximal and distal muscle groups using mechanic/enzymatic dissociation and magnetic-activated cell sorting technique. Purified primary cells were cultured and pro-inflammatory, adhesion and MHC molecule expression were analyzed under basal or stimulated conditions (TH1 cytokines: TNFα and IFNγ; Type I interferons: IFNα and IFNβ) via qPCR and flow cytometry. Produced chemokines were detected by LEGENDplex immunoassay.

**Results:** Under basal conditions, pmMCs of distal muscle groups show enhanced expression levels of pro-inflammatory, adhesion and MHC molecules on their surface. However, pmMMECs of distal muscle groups are characterized by a higher expression of MHC-1. Besides, pmMMECs of the proximal arm display a higher expression of ICAM-1 and VCAM-1 compared to pmMMECs of the distal arm. After stimulation with TNFα and IFNγ pmMCs and pmMMECs of distal muscle groups demonstrate increased expression levels in most of the pro-inflammatory markers, adhesion molecules and MHC complexes. In contrast, an opposed effect of this pattern could be seen at some molecules after a treatment with IFNα and IFNβ: pmMCs of the proximal arm display an enhanced expression of MHC-1 and CD80 compared to the distal arm. In addition, pmMMECs of proximal muscle groups show a higher expression of MHC-1. Furthermore, chemokine secretion by pmMCs and pmMMECs shows distinctive patterns in the different muscle groups (e.g. TARC, KC, Eotaxin, MIP-1α).

**Conclusion:** The distinct immunological properties in the different muscle groups might explain the specific clinical patterns observed in IIM. However, the regulatory mechanisms and the interaction between the different cell-types still need to be further elucidated. These insights might help to identify new, more specific and urgently needed therapeutic targets.

## P82

### Work disability in patients with idiopathic inflammatory myopathies in moldovan myositis group

Natalie Loghin-Oprea, Snejana Vetrila, Lucia Mazur-Nicorici, Virginia

Salaru, Minodora Mazur

State University of Medicine and Pharmacy Nicolae Testemitanu,

Chisinau, Moldova

**Correspondence:** Natalie Loghin-Oprea

BMC Rheumatology 2019, **3**(Suppl 1):P82

**Objectives:** To assess the disability and work productivity in patients with idiopathic inflammatory myopathies

**Methods:** We performed a cross-sectional study from December 2017 to September 2018, patients included fulfilled the ACR/EULAR classification criteria for IIM. Demographic and clinical data were collected.
Consistent with the objective we applied the modified Rankin scale for determining disability. To assess the work productivity, we used Work Productivity and Activity Impairment: General Health (WPAI) questionnaire, that was administered only in employed subjects. The study was performed according to the Declaration of Helsinki for human rights and signed the informed consent. Statistical data was analyzed using MedCalc software version 12.

Results: There were 67 patients enrolled in the study, including 51 females and 16 males with a F:M ratio of 3.2:1, mean age at the time of assessment was 53.1±12.5 (range 25-78) years. The mean disease duration was 8.3±5.3 (range 0.5-12) years. In the study group the disability, according to Rankin scale, was determined as follows: 1st degree – 21 (31.34 %), 2nd degree – 26 (38.81 %), 3rd degree – 11 (16.41 %), 4th degree – 8 (11.94 %), 5th degree was established in one patient. To be noted that 0 and 6th degree was not determined in the study group. The employment status was appreciated in 19 patients: 10 (14.93 %) worked full-time and 9 (13.43 %) part-time, only 4 (5.97 %) patients with disease duration less than 2 years were employed. The mean absenteeism score was 17.06±21.27 (range 0-86.5) %, presenteeism – 26.47±21.20 (range 0-70)%, work productivity loss – 36.19±28.09 (range 1-93.25)% and activity impairment was calculated 28.82±22.33 (range 0-80) percent. We analyzed multiple variables in order to establish which determine loss of productivity and was found moderate correlation between absenteeism and muscle force, r=0.46, p<0.05.

Conclusions: Patients with idiopathic inflammatory myopathies have diverse degree of disability, with majority from slight to moderate. The muscle force impairment seems to be the main cause of reduced work productivity.

## P83
### Investigating the Sensitivity and Specificity of the Myositis Profile-4 EUROLINE assay

Clara Ventín-Rodríguez<fnref n="1" />, James Lilleker<fnref n="2" />, Shuayb Elkhalifa³, Hector Chinoy<fnref n="2" />

**Correspondence:** James Lilleker

BMC Rheumatology 2019, **3**(Suppl 1):P83

**BACKGROUND:** The Myositis Profile-4 EUROLINE immunoblot (EUROIMMUN AG, Germany) includes 16 autoantibodies (Mi2-alpha, Mi2-beta, TIF1-gamma, MDA5, NXP2, SAE1, KU, PM-Scl75, PM-Scl100, Jo1, SRP, PL-7, PL-12, EJ, OJ, Ro52) and is increasingly used in the workup of patients with suspected idiopathic inflammatory myopathy (IIM). Sensitivity is high, but concerns have been raised about low specificity for IIM. We investigated the sensitivity and specificity of antibody positivity for IIM using this assay.

**METHODS:** All patients tested using the Myositis Profile-4 EUROLINE immunoblot between January of 2016 and July 2018 at a UK hospital were identified. Assay results were matched to clinical data (highest creatine kinase [CK] level, electromyogram, muscle biopsy, pre-test working diagnosis and final diagnosis) collected retrospectively.

**RESULTS:** Of 401 identified patients, accompanying clinical data was available for 349 (87%), 65% (226/349) were female and the mean age was 54 years (SD 14). Strong and weak antibody positivity was found for 23% (79/349) and 19% (66/349) of patients respectively. Dual strong specificities were found in 5% (18/349). Pre-test working diagnoses were categorised as "IIM" (27%, 94/349), "other connective tissue diseases (CTDs) without suspected muscle involvement" (40%, 139/349) and "myopathic syndromes with low probability of IIM" (33%, 116/349). The likelihood of any strong positive result was highest for those with suspected IIM (38%, versus 21% and 12% respectively, p < 0.001). Weak positivity was found at a similar rate across the three groups (20%, 20% and 16% respectively, p = 0.709). The false positive rate for strong antibody positivity was 15% (40/266) overall, highest for those with a pre-test working diagnosis of CTDs without suspected muscle involvement (20%, 28/137) and myopathic syndromes with low probability of IIM (10%, 11/110), compared to 5% (1/19) for those with a pretest diagnosis of IIM. Sensitivity and specificity for IIM of any strong antibody positivity was 47% and 85% respectively. Only a

pre-test working diagnosis of IIM was associated with increased likelihood of strong antibody positivity (46% (36/79), versus 22% (58/270) in the antibody negative group, OR 3.1 (95%CI 1.80-5.20, p < 0.001)), with no associations demonstrated for age, gender, myopathic electromyogram, CK level or inflammatory muscle biopsy.

**CONCLUSION:** Strong antibody positivity using this EUROLINE immunoblot showed moderate sensitivity and high specificity for IIM. False positive results were common especially in those where the pre-test probability of IIM was low, potentially leading to unnecessary further investigation in such cases.

## P84
### A longitudinal analysis of anti-FHL1 antibodies in a Swedish cohort of patients with Idiopathic Inflammatory Myopathies

Ángeles Shunashy Galindo-Feria<fnref n="1" />, Eliska Divišová<fnref n="2" />, Cátia Fernandes-Cerqueira<fnref n="1" />, Maryam Dastmalchi<fnref n="1" />, Edvard Wigren<fnref n="1" />, Susanne Gräslund<fnref n="1" />, Ingrid. E. Lundberg<fnref n="1" />

¹Karolinska Institutet, Stockholm, Sweden; ²Charles University, Prague, Czech Republic

**Correspondence:** Ángeles Shunashy Galindo-Feria

BMC Rheumatology 2019, **3**(Suppl 1):P84

**Objectives:** Antibodies targeting a novel and muscle-specific autoantigen, the Four-and-a-half-LIM-domain 1 (anti-FHL1), have been identified in patients with idiopathic inflammatory myopathies (IIM). The aim of this project was to evaluate when anti-FHL1 autoantibodies are present in the course of the disease and if autoantibody titers vary over time.

**Methods:** The anti-FHL1 antibody status was obtained from a previous serological cross-sectional analysis from where we selected sera from IIM anti-FHL1+ patients (n=25) and sex and age matched sera from IIM anti-FHL1- patients (n=51), and healthy controls (HCs, n=50). Levels of anti-FHL1+ autoantibodies were evaluated by ELISA. Patients included in the study had at least one sample available at time of diagnosis and one consecutive serum sample within an interval of 36 months. All patients were followed at the Division of Rheumatology, Karolinska University Hospital from January 1982 to December 2017. HCs sera collected at a single time point were tested.

**Results:** In the IIM group we included 76 patients with a total of 320 serum samples. Median follow-up time was 108 months, with median of 4 samples available per patient. In total, we identified the presence of anti-FHL1+ antibodies in n=31 IIM patients, corresponding to the group of anti-FHL1+ (n=25) and in anti-FHL1- (n=6) from the cross-sectional analyses. One HC had positive anti-FHL1 titers. We subdivided the patients into 4 groups: anti-FHL1+: "highly positive" (O.D.>0.75, n=11), "intermediate positive" (1>O.D.>0.75, n=6), "baseline negative" that seroconverted (O.D.>0.75, n= 14), and one anti-FHL1 "negative" group. All groups were compared by given OD medians at each of the point of observation. Highly positive patients had persisting high anti-FHL1 titers during the follow-up; on the contrary, both intermediate positive and baseline negative groups were fluctuating around the cut-off point. Eight of 14 (57%) patients from the group "baseline negative" seroconverted to anti-FHL1+ within the first 36 months. The anti-FHL1 "negative" group presented constant low antibody titers during the longitudinal follow-up.

**Conclusions:** Anti-FHL1 antibody positivity was detected in patients with high titers of anti-FHL1+ autoantibodies in the first available serum sample or developed within the first 36 months after diagnosis and persisted over many years. A group of patients with intermediate levels had fluctuating positivity over the years. It is still unknown if the anti-FHL1 antibody titer is a marker of prognosis and/or damage in IIM; thus, clinical data needs to be addressed, and in-vitro experiments and biochemical characterization of this autoantibody are still required.

## P85
### Shear Wave Elastography; Preliminary Validation and Diagnostic Utility in the Evaluation of Muscle

Shereen Paramalingam, Helen Keen, Merrilee Needham

Fiona Stanley Hospital, Murdoch, Australia

**Correspondence:** Shereen Paramalingam

BMC Rheumatology 2019, **3**(Suppl 1):P85

<footnote n="1">¹Complejo Hospitalario Universitario de A Coruña, A Coruña, Spain;</footnote>

<footnote n="2">²University of Manchester, Manchester, UK; ³Salford Royal Hospital, Salford, UK</footnote>
**Background:** Idiopathic inflammatory myopathies (IIM) is a rare, heterogeneous group of acquired muscle diseases characterised by progressive muscle weakness. Shear wave elastography (SWE) is a novel ultrasound (US) technique that uses acoustic radiation force impulse (ARFI) to generate a shear wave which estimates shear wave speed (SWS) and ultimately tissue elasticity of muscle. There is currently no standardised methods to evaluate muscle using SWE.

**Objective:** The objective of this study is to begin validation of SWE as an outcome tool in muscle disease.

**Methodology:** This is a pilot cross-sectional study looking at an incident group of IIM (n=10) and healthy controls (n=30) using US (grey scale B mode and power Doppler) and SWE in the evaluation of muscle. All patients (n=40) will receive US (grey scale B mode and power Doppler) and SWE over the deltoid and vastus lateralis and just US (grey scale B mode and power Doppler) over the flexor digitorium profundus, flexor carpi ulnaris, tibialis anterior and lateral gastrocnemius muscle. All patients will have routine clinical assessments- Manual Muscle Testing (MMT8 and MMT26), patient and physician Visual Analogue Scale (VAS), Health Assessment Questionnaire (HAQ) score, laboratory assessments (full blood picture (FBC), urea and creatinine (U&E), alanine aminotransferase (ALT), creatine kinase (CK), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) and an additional myositis serology, antinuclear antibody (ANA), extractable nuclear antigen (ENA) and HMG CoA Reductase enzyme for the IIM group. The incident (n=10) IIM group will have clinically indicated magnetic resonance imaging (MRI) that will be used as a comparator to SWE. The initial data analysis is descriptive, with non-standardly distributed data being analysed with non-parametric tests. Linear regression analysis will be used to determine the association between SWS and other commonly used measures of muscle disease. Logistic regression will be used to determine the sensitivity and specificity of SWS in distinguishing between diseased and control participants. Results: Pending, to be finalised prior to GCOM 2019

**Conclusion:** SWE may have a role in both the research and clinical setting when managing patients with IIM

P86

Comparing muscle ultrasound to whole body muscle magnetic resonance imaging to as biomarker of disease activity in patients with new-onset myositis: a prospective cohort study

Johan Lim<fnref n="1" />, Frank Smithuis<fnref n="1" />, Esther Brusse², Jessica Hoogendijk³, Christiaan Saris⁴, Marije Wolvers<fnref n="1" />, Rob De Haan<fnref n="1" />, Eleonora Aronica<fnref n="1" />, Mario Maas<fnref n="1" />, Marianne De Visser<fnref n="1" />, Filip Eftimov<fnref n="1" />, Camiel Verhamme<fnref n="1" />, Anneke van der Kooi<fnref n="1" />

**Correspondence:** Johan Lim

BMC Rheumatology 2019, 3(Suppl 1):P86

**Objective:** Biomarkers of disease activity in myositis lack varying degrees of diagnostic accuracy, which may consequently lead to both under and overtreatment. Muscle ultrasound (US) and muscle Magnetic Resonance Imaging (MRI) are two non-invasive biomarkers used in clinical practice, however, no direct comparisons have been made. Therefore, we conducted this observational study to compare US to MRI as diagnostic biomarkers and as marker of disease activity during follow-up in new-onset patients with myositis.

**Methods:** Cohort of myositis patients (excluding inclusion body myositis) who were included in the ongoing IMMEDIATE study (NTR6160). All patients were clinically assessed before and after nine weeks of IVIg monotherapy by the IMACS Core Set Measures (CSMs) and Total Improvement Score (TIS). US (Esaote SpA, Genoa, Italy) consisted amongst others of quantitative gray-scale analysis of muscle echointensity (EI) and quantitative analysis of subcutis, fascia, and muscle diameter. Whole body MRI (WB-MRI) (Philips, Best, The Netherlands) consisted

amongst others of 2-point Dixon (3 Tesla) generated coronal and axial T2-weighted fat-suppression 2D images in which 42 muscles and 8 fascia/subcutaneous locations were semi-quantitatively scored for edema.

**Results:** So far, we included 16 patients: dermatomyositis (n=8), non-specific myositis/overlap myositis (n=3), immune-mediated necrotizing myopathy (n=4), and anti-synthetase syndrome (n=1). We intend to include four other patients. We will present results of baseline assessment of US and MRI and of changes over time after nine weeks of IVIg therapy. We will explore discriminating validity of various imaging parameters between responders and non-responders, and explore correlations with clinical parameters (amongst others IMACS CSMs).

**Conclusion:** This study may show the usefulness of ultrasound and MRI as biomarkers of disease activity in new-onset patients with myositis.

P87

May the muscular MRI identify a pattern of muscular involvement in patients with idiopathic inflammatory myopathies? Analysis of a monocentric cohort

Simone Barsotti, Mugellini Barbara, Alessandra Tripoli, Giacomo Aringhieri, Chiara Cardelli, Elisa Cioffi, Virna Zampa, Davide Caramella, Marta Mosca, Rosella Neri
University of Pisa, Pisa, Italy

**Correspondence:** Simone Barsotti

BMC Rheumatology 2019, 3(Suppl 1):P87

**Objective:** In patients with idiopathic inflammatory myopathies (IIM), magnetic resonance imaging (MRI) has been proposed as a useful tool for both the diagnosis and the follow-up, but the clinical significance and the pattern of muscular involvement in IIM patients still remains undefined. The primary aim of this study is to analyse the presence of MRI alterations (muscular edema, fatty infiltrates and atrophy) and their correlation with clinical parameters and to evaluate the possible difference in the pattern of muscular alterations between disease subsets in IIM patients.

**Methods:** We retrospectively collected data from IIM patients (EULAR/ACR criteria) who performed a MRI of pelvic and thigh muscles from 2010 to 2017: 27 had dermatomyositis and 58 polymyositis, mean age of 58.6±13.4 years and mean disease duration of 45±73 months. The images were assessed by a dedicated radiologist in 23 muscles for the presence of muscular edema, fatty infiltrates and atrophy. Moreover, data about serum creatine kinase (CK) and manual muscle test 8 (MMT8) were collected. Data were reported as median±interquartile range, non-parametric tests were used for the analysis.

**Results:** Sixty-three patients presented muscular edema in at least one muscle. The muscular edema was higher in patients with lower disease duration (9.5±47.0 vs 19.8±97.2 p=0.031). Patients with muscular edema had higher CK levels (1506±1976 vs 235±224 p=0.001) and lower MMT8 (63.6±11.2 vs 69.8±10.7 p=0.031). Forty-eight patients presented fatty infiltrates that were more present in older patients (p=0.01) and in those with longer disease duration (39.1±95.4 vs 9.5±12.5 p=0.024). At multivariate analysis disease duration represented the only independent factor for the presence of muscular fatty infiltrates (p=0.05). Muscular atrophy was present in 17 patients but it was not correlated to age and disease duration. CK and MMT8 were not different in presence/absence of fatty infiltrates or muscular atrophy. Edema and atrophy were not different between poly- and dermatomyositis, while fatty infiltrates were more present in the posterior compartment (biceps femoris and semitendinosus muscle) in patients with PM compared to DM (68.2% vs 29.6% p=0.046).

**Conclusions:** The alterations identified with MRI are different according to disease duration and the pattern of the fatty infiltration, but not of the inflammation, may present a different distribution between patients with dermatomyositis and polymyositis. Despite the use of MRI for patients with IIM may provide additional information for clinical and biochemical examination, the role for the differential diagnosis and in the follow-up needs to be confirmed.

<footnote n="1">¹University of Amsterdam, Amsterdam, Netherlands; ²Erasmus MC, Rotterdam, Netherlands; ³UMC Utrecht, Utrecht, Netherlands; ⁴Radboud University, Nijmegen, Netherlands</footnote>
P88

**Recovering autonomy is a key advantage of home-based immunoglobulin therapy in patients with myositis: a qualitative research study**

Patrick Chérin¹; Taylor Pindi²; Pierre Clerson³; Annaik Dokhan⁴; Yann Fardini³; Martin Duracinsky⁵; Jean-Chrales Crave²; Olivier Chassany⁵
¹Pitié-Salpetrière Hospital, Paris, France; ²Octapharma, Boulogne-Billancourt, France; ³Soladis Clinical Studies, Roubaix, France; ⁴Sirius Customizer, Paris, France; ⁵University Paris-Diderot, Paris, France

**Correspondence:** Taylor Pindi

BMC Rheumatology 2019, **3**(Suppl 1):P88

**Purpose:** Immunoglobulins are second or third-line treatments in dermatomyositis (DM) or polymyositis (PM) refractory to high-dose corticosteroids and immunosuppressants. Immunoglobulins (2g/kg/ month) are usually administered intravenously (IVIg) once a month and the patient have to stay at hospital for a few days. Recently, sub- cutaneous injections (SCIg) have been proposed 2-3 times per week, in some dysimmune diseases. SCIg are administered at home either by the patient himself or by a nurse. We investigated the needs and attitudes of DM and PM patients having the experience of IVIg and SCIg. Patients and methods: Seven patients (6 PM and 1 DM) from a single centre participated in a focus group (N=6) or underwent in- depth interview (N=1). Five patients had the experience of both IVIg at hospital and SCIg at home; one patient has received only IVIg at hospital. Verbatim was recorded and transcribed for further content analysis and computer-aided textual analysis.

**Results:** Clinical profiles and stories were heterogeneous. At diagnosis, muscle weakness but also severe pain and fatigue were at the forefront of patients' complaints impairing daily life and autonomy. Patients re- ported to be considerably improved with immunoglobulins. All patients with experiences of both IVIg and SCIg expressed their preference for SCIg which were described as easy, less disruptive for daily life, well tolerated and less time-consuming. SCIg self-administration at home re- stored their feeling of autonomy and control. Patients appreciated to be considered actors of their own treatment.

**Conclusion:** In-depth interviews of DM and PM patients revealed that recovering autonomy and control was a central advantage of home- based SCIg. Home-based SCIg were efficient, well-tolerated and per- ceived as a good compromise between treatment burden and efficacy.

**Keywords:** In-depth interviews, focus group, textual analysis, myositis, patients expectations, preference, immunoglobulins, autonomy

P89

**Muscle Function and Health-Related Quality of Life in Patients with Polymyositis and Dermatomyositis**

Kristofer Andreasson, Li Alemo Munters, Helene Alexanderson
Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Kristofer Andreasson

BMC Rheumatology 2019, **3**(Suppl 1):P89

**Objective:** The objective is to investigate muscle function in terms of maximal voluntary isometric strength (MVIC) and isometric muscular endurance (ME) in patients with newly onset and established PM/ DM. A further objective is to investigate if there is a correlation be- tween muscle function and health related quality of life (HRQoL).

**Methods:** Patients diagnosed with PM or DM (n=8) during September 2017 and September 2018 at Karolinska University hospital in Solna who met the inclusion criteria were asked to participate. Patients with established PM/DM (n=7) where identified through patient register at the same clinic, selected to match the patients with recent onset disease as to age and gender. To asses MVIC and ME, a Biodex dynamometer was used. Three maximum, 4-second-contractions, with a three-minute rest in-between were performed followed by six sets of twelve submaximal contractions ranging from 20 % to 70 % of MVIC. Each set ended with a new maximum repetition registered as percentage of MVIC. SF-36 was used to measure HRQoL. Statistical significance was set to p < 0.05, Mann-Whitney U-test was used to calculate group differences and Spearman's rho for correlations.

**Results:** Median age for patients with recent onset PM/DM was 34 (range 19-64) years and for established disease 58 (28-66) years. Diagnosis duration was 5.5 (1-6) months and 7.4 (6-36) years for the two groups, respectively. Patients with recent onset disease had a median MVIC of 73 (45-127) Nm and patients with established dis- ease had 70 (41-118) Nm (p=0.46). Patients with recent onset disease and established PM/DM had ME 83 (63-94) % and 91 (85-98) %, re- spectively (p=0.01). Moderate correlations were found between ME and Vitality (rs=0.56, CI (0.07;0.84) and ME and Physical Role function (rs=0.54, CI (0.03;0.82). There were weak correlations between ME and Physical Function, General Health and Social Function varying between (rs=0.41, CI (-0.13;0.76) and (rs=0.49, CI (-0.03;0.8). A nega- tive and weak correlation between MVIC and Role Emotional was found (rs=-0.3, CI (-0.71;0.25) with even lower correlations to remaining domains.

**Conclusion:** Patients with recent onset PM/DM seem to have reduced ME compared to patients with established disease. No differences were found regarding maximal voluntary isometric contraction (MVIC). Moderate correlations were found between ME and Vitality and Physical Role function. Other correlations were weak at best. More patients need to be included to reach statistical power to con- firm these preliminary results.

P90

**Living with idiopathic inflammatory myopathies – patients’ thoughts, fears, and expectations**

Hedvig Engberg, Helene Alexandersson, Marie Holmqvist
Karolinska Institutet, Stockholm, Sweden

**Correspondence:** Marie Holmqvist

BMC Rheumatology 2019, **3**(Suppl 1):P90

**Background:** Being diagnosed with idiopathic inflammatory myop- athies (IIM) alters your life. Little is known of how patients with IIM ex- perienced their period of diagnosis, what they think we should focus on Our aim was therefore to understand the self-experienced difficul- ties patients with IIM face, to gain a deeper knowledge of the experi- ences with health care patients with IIM have, and to find out what patients with IIM would like health care and researchers to focus on continuing forward.

**Methods:** To answer these questions we asked 12 patients with IIM who were followed at the division of rheumatology for consent to interview them. Patients with overlap disease were excluded from participation. Semi-structured interviews were conducted at patients most convenient location, which often was in their home or at the division of rheumatology. The interviews were conducted by a trained medical student, and all interviews were recorded, tran- scribed and coded by three of the authors. A thematic analysis was performed.

**Results:** Twelve patients were interviewed between January and Feb- ruary 2018. Median age was 64 years of age at interview (range 45- 85), 9 were women, 3 were men. They had a median disease dur- ation of 11 years (range 2-37 years). The results from our interviews were primarily x: 1. we found that the time period up until diagnosis was very emotionally excruciating. Patients had for a long time felt something was not right, and had several contacts with health care facilities, before somebody realized what was the underlying prob- lem. Not being believed was reported to be difficult. 2. Patients need more disease specific information than we are giving them. They also requested more and detailed information about follow up and prog- nosis of their disease. Further, it was also expressed that being able to discuss their entire life-situation with a physician, specialized in IIM, was of pivotal importance. Being diagnosed and seriously ill at the time of diagnosis also conferred a traumatic experience patients wanted to talk about. Unfortunately, patients also reported that the diagnosis has lead to isolation for them. Their fear of infections and a wish to remain “who they had always been” made patients refrain from socializing with friends and family.

**Conclusion:** We need to focus more on the holistic care of these pa- tients. Many have traumatic experiences and wish to discuss their lives with their physician.
## P91

### Persons with polymyositis and dermatomyositis experience reduced work ability and quality of life

Malin Regardt, Karin Aström

Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Malin Regardt

BMC Rheumatology 2019, **3**(Suppl 1):P91

**Objective:** To describe self-rated work ability with two different assessments and quality of life in persons with PM and DM. To investigate correlations between self-rated work ability and quality of life.

**Method:** Participants were identified through the Swedish Myositis Network registry (SweMyoNet). Of 78 possible participants, 48 agreed to participate in this study. The median (IQR) age were 57 (45-61) years with a median disease duration of 6 (2-14) years. Fifty-three percent of the participants were women. Seventy-seven percent were working, and the remaining were on sick-leave. Self-rated work ability was measured by the questionnaire Work Ability Index (WAI) and the Work Ability Score (WAS) which is a single item question. Quality of life by the SF-36.

**Results:** Self-rated work ability measured by WAI in persons with PM and DM varied between poor work ability and good work ability. The median value of the group was 34 which indicates less good work ability. Self-rated work ability measured by WAS varied between poor work ability and good work ability. The median of the total group indicates less good work ability. There was a strong correlation between self-rated work ability measured by WAI and WAS (rs 0,879 p = 0,01). Quality of life measured by SF-36 were rated lower in persons with PM and DM when compared to the general population in dimensions; Physical Function, Role-Physical, General Health, Vitality and Social function (p ≤ 0.02). There were moderate to high correlations between self-rated work ability measured by both WAI and WAS, and all dimensions of SF-36 (p < 0.01).

**Conclusion:** Persons with PM and DM self-rated their work ability as poor and the quality of life were significantly reduced when compared to the general population. The measures WAI and WAS correlates highly with each other and revealed comparable results indicating that WAS may work as well as WAI as a screening tool to identify reduced work ability. The WAS may also be more feasible with just one single question to use in clinical practice. Our results indicate the importance to measure self-rated work ability in persons with PM and DM in clinical practice.

## P92

### Female Sexual Function Impairment in Idiopathic Inflammatory Myopathies

Barbora Heŕmánková, Maja Spiritovic, Sabina Oreska, Hana Storkanova, Karel Pavelka, Ladislav Senolt, Herman Mann, Jiri Vencovsky, Michal Tomcik

Institute of Rheumatology, Prague, Czech Republic

**Correspondence:** Barbora Heŕmánková

BMC Rheumatology 2019, **3**(Suppl 1):P92

**Objectives:** Idiopathic inflammatory myopathies (IIM) are characterized by chronic muscle inflammation and involvement of internal organs which leads to functional impairment, reduced quality of life including sexual life. The aim of this study was to assess sexual functions/quality of life and pelvic floor function in female IIM patients compared to age-/sex-matched healthy controls (HC) and to analyze the potential impact of disease activity, fatigue, physical activity and depression.

**Methods:** In total, 22 women with IIM [mean age: 55.1, disease duration: 7.9 years, dermatomyositis (DM, 8)/ polymyositis (PM, 10)/ necrotizing myopathy (IMNM, 3)/ inclusion body myositis (IBM, 1)], who fulfilled the Bohan/Peter 1975 criteria for DM/PM, and 22 healthy controls (mean age: 55.1 years) filled in 12 well-established and validated questionnaires assessing sexual function and pelvic floor function, fatigue, physical activity and depression. We used the following questionnaires: Female Sexual Function Index (FSFI), Brief Index of Sexual Function for Women (BISF-W), Sexual Quality of Life Questionnaire

(SQoL-F), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12), Pelvic Floor Distress Inventory Questionnaire (PFIQ7), Fatigue Impact Scale (FIS), Beck's Depression Inventory II (BDI II), Health Assessment Questionnaire (HAQ) and Human Activity Profile (HAP).

**Results:** Compared to HC, patients with IIM had significantly higher prevalence and greater severity of sexual dysfunction (FSFI, BISF-W: in all subscales as well as total scores), dysfunction of pelvic floor (PISQ-12), and worse sexual quality of life (SQoL-F). Worse scores in IIM patients were associated with elevated muscle enzyme levels [lactate dehydrogenase: FSFI (r=-0.524,p=0.0123), BISFW (r=-0.528,p=0.0115)], greater fatigue [FIS: FSFI (r=-0.434,p=0.0438), BISF-W (r=-0.488, p=0.0211), SQoL-F (r=-0.488,p=0.0070), PISQ-12 (r=0.643,p=0.0013)], more severe depression [BDI-II: PISQ-12 (r=0.474,p=0.0258)], deteriorated quality of life [HAQ: PISQ-12 (r=0.476,p=0.0252)], and worse ability to perform physical activities [HAP: FSFI (r=0.437,p=0.0417), BISF-W (r=0.451,p=0.0351), PISQ-12 (r=-0.494,p=0.0195)].

**Conclusions:** Women with IIM reported significantly impaired sexual function, sexual quality of life and pelvic floor function compared to age-matched healthy controls. Worse scores in IIM were associated with disease activity, physical activity, fatigue, depression and quality of life. Acknowledgements: Supported by AZV-16-33574A, MHCR 023728, and SVV - 260373.

## P93

### Experience of pain in polymyositis and dermatomyositis – a qualitative study

Helene Alexanderson, Masoumeh Tasarrofi, Malin Regardt

Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Helene Alexanderson

BMC Rheumatology 2019, **3**(Suppl 1):P93

**Objective:** Studies indicate that adults with polymyositis (PM) and dermatomyositis (DM) have higher self-reported pain compared to general population assessed by the SF-36 domain, Bodily pain (BP). International focus groups and online surveys indicate that pain is an important symptom in PM/DM. Knowledge on myositis-related pain is limited. The objective was to explore experience of pain in adults with PM and DM.

**Methods:** Patients with adult PM/DM were strategically identified to represent genders, various ages, self-reported pain, diagnosis duration, and disease activity. Inclusion criteria: age > 18 years, VAS pain >10 mm. Exclusion criteria: diagnosis of fibromyalgia or other inflammatory rheumatic disease. Individual interviews using a semi-structured interview guide were conducted. Patients completed the SF-36 survey after the interview. Interviews were audiotaped and transcribed verbatim. Qualitative content analysis was performed by two researchers separately followed by a consensus discussion.

**Results:** Six patients were included; female n= 4, PM n=4, median (range) age 44.5 (28-71), diagnosis duration 5 (1-22) years, physician global VAS 15 (0-40) mm, pain VAS 66 (30-84) mm. SF-36 BP was 31.5 (22-74), more pain compared to reference value of 70. Three over-arching THEMES, 12 categories and 21 subcategories (subcat) were identified. Theme 1: PAIN WAS WORST IN THE BEGINNING, WAS REDUCED BY CORTICOSTEROIDS, BUT RETURNED WITH TAPERING OF MEDICATION TO SUSTAINED, EVEN WORSENING LEVELS OVER TIME, Category-Factors increasing the pain, (subcat/over exertion, tapering of corticosteroids, cold climate), Category-Factors reducing pain, (subcat/warm climate, medication/adapted exercise, self-management), Category-Localization and character of pain, (subcat/pain was first myositis symptom, pain in muscles and joints, constant pain), Category-Thoughts about pain, (subcat/myositis causes pain, pain is a subjective symptom, fatigue have worse life-impact than pain). Theme 2: INFORMATION ABOUT PAIN IS IMPORTANT, Category-Information from health-care providers (HCP), (subcat/inadequate and wrong information, HCP don't care about how pain impacts sex-life). Theme 3: PAIN INFLUENCES QUALITY OF LIFE, Category-Social life, (subcat/reaction from family, friends and colleagues, pain hinders social activities), Category-Emotions, (subcat/don't want to show or talk about my pain, anger, grief and frustration, relief by other's support), Category-Pain impact on daily activities, (subcat/pain impacts sleep, pain limits daily activities).
**Conclusion:** Pain seems to be a myositis symptom and could be the first symptom of myositis, could initially be reduced by corticosteroids but worsens with tapering of medication and remain as a chronic symptom worsening over time. HCP need to ask about, measure and give correct information about myositis-related pain.

## P94

### A novel autoantibody against DNA damage binding protein-1 in idiopathic inflammatory myopathy

Yuji Hosono
National Institutes of Health, Bethesda, USA
BMC Rheumatology 2019, **3**(Suppl 1):P94

**Objective:** Many kinds of myositis specific autoantibodies (MSAs) are detected in idiopathic inflammatory myopathy (IIM) patients. These are useful to diagnose, predict the clinical course, and assess therapy in IIM at an early stage. Here we describe and characterize the clinical significance of a novel autoantibody in IIM directed against the DNA damage binding protein-1 (DDB-1).

**Methods:** 380 patients with various connective tissue diseases (CTDs) and 20 healthy controls (HCs) were screened for autoantibodies by immunoprecipitation with [35S] methionine-labeled HeLa cells. The target autoantigen was immunoaffinity-purified from HeLa cell extracts and was subsequently identified by peptide mass fingerprinting. Antigen specificity of the serum was further examined by immunoblotting.

**Results:** An antibody directed against a 120kDa protein was detected in sera from 6 patients with IIM, but not in the sera from other CTD patients or HCs. No patient with anti-120kDa antibody was positive for other myositis-specific autoantibodies. 83% (5 of 6) were polymyositis and 17% (1 of 6) was DM. None with anti-120kDa antibody had complicated cancer. All except 1 (83%, 5 of 6) were negative for antinuclear antibody. Most anti-DDB-1 positive patients (67%, 4 of 6) showed spontaneous improvements without immunosuppressant treatment. Peptide mass fingerprinting and immunoblotting identified DDB-1 as the corresponding autoantigen recognized by anti-120KDa autoantibody.

**Conclusions:** The anti 120kDa antibody which recognized DDB-1 was a novel marker of IIM. Anti-DDB-1 antibody detection may be helpful for diagnose and have prognostic and therapeutic implications in patients without known MSAs. Our findings may shed new insights into the pathogenesis of IIM.

## P95

### Evaluation of the effect of neutralizing anti-IFN-α antibodies produced in one SLE patient vaccinated with IFN-K on myotubes atrophy induced by type I interferon

Alexandrine Mahoudeau; Leandro Ladislau; Yves Allenbach; Thérèse Croughs; Allia Gati; Céline Anquetil; Damien Amelin; Olivier Benveniste

**Correspondence:** Alexandrine Mahoudeau
BMC Rheumatology 2019, **3**(Suppl 1):P95

Dermatomyositis is an acquired auto-immune disease characterized by skin or muscle lesions and muscle-specific pathological features such as perifascicular muscle fibre atrophy and vasculopathy. Dermatomyositis patients display an upregulation of type I interferon-inducible genes in muscle fibres, endothelial cells, skin, and peripheral blood. We have shown in vitro that the activation of type I interferon in differentiating myoblasts abolished myotube formation with reduced myogenin expression while in differentiated myotubes, we observed a reduction in surface area and an upregulation of atrophy-associated genes (L Ladiislau et al. Brain 2018; 141(6):1609-1621). Here, our aim was to evaluate in the same in vitro system, the effect of polyclonal human anti-IFN-α neutralizing antibodies (referred to as anti-IFN-α patient Abs) induced in a lupus patient treated with an immunotherapeutic vaccine interferon-α-kinoid (IFN-K, Neovacs, NCT01058343-Phase I/IIa study-IFN-K-001, 4 injections of IFN-K at 120 µg, BR Lauwerys et al. Arthritis Rheum. 2013;65(2):447-56). Myotubes were treated with recombinant

human interferon alpha 2b (IFN-α, 103 U/mL), and with monoclonal anti-human interferon alpha (anti-IFN-α mAb, Clone MMHA-11), or purified mouse IgG1 isotype control (ISO), or anti-IFN-α patient Abs corresponding to total purified IgG from serum of the patient vaccinated with IFN-K (50µL at 1 mg/mL, total IgG purified with NabTM Protein G Spin Kit, Thermo Scientific). To assess the effect of IFN-α pathway activation on myotube surface area, myotubes were immunostained with anti-myosin heavy chain (hybridome, clone MF20) and total surface area was evaluated using the Cell Profiler® software and ImageJ® software (L Ladislau et al. Brain 2018; 141(6):1609-1621). As expected, an atrophy of the myotubes incubated with IFN-α+ ISO (262542 µm²) compared to untreated myotubes (ISO, 448338µm², p< 0.001) was observed. This atrophic effect was not observed when anti-IFN-α mAb, or anti-IFN-α patient Abs were added to the media (434389 µm² p=0.9; 423360 µm² p=0.6, respectively). Anti-IFN-α patient Abs induced after in vivo vaccination by IFN-K in lupus patients have a neutralizing effect on the in vitro bioeffect of IFN-α on myotubes. This observation paves the way of IFN-K as a potential therapeutic approach for dermatomyositis patients.

## P96

### Patients with inflammatory myopathies admitted in intensive care unit are characterised by recent onset and untreated active disease as well as older age and high comorbidities

Baptiste Michard, Thierry Artzner, Francois Severac, Julien Pottecher, Jean Sibilia, Bernard Geny, Alain Meyer¹
CHU de Strasbourg, Strasbourg, France

**Correspondence:** Alain Meyer
BMC Rheumatology 2019, **3**(Suppl 1):P96

**Background:** The characteristics of adults patients with inflammatory myopathies (IM) admitted to intensive-care unit (ICU) have not yet been assessed.

**Objectives:** To assess the clinical features, risk-factors and outcome of patients with IM admitted in ICU.

**Methods:** A single-centre cohort of 509 patients with IM was screened for admission in ICU from 1992 to 2017. Control-patients with IM who had not been hospitalised in ICU were randomly selected.

**Results:** 32 ICU-admissions were recorded in 27 IM-patients. Characteristics and prognosis of IM-patients in ICU. Patients hospitalised in ICU had a mean age of 63±15 years with SAPS II score of 58±24 and LODS score of 9±5 corresponding to an intermediate severity at admission in ICU. The delay between IM diagnosis and first ICU-admission was 27±43 months. Twelve patients (44%) were admitted within the first month of IM diagnosis, among whom 4 (15%) were diagnosed with IM during ICU stay. Sixteen patients (60%) were not treated at the time of their first ICU-admission. In 56% of the ICU stays, patients had active disease at admission. Patients were most frequently admitted for respiratory failure (88%) but cardiac (47%), renal (47%), neurologic (47%), haematological (22%) and hepatic (15%) failures were also recorded. Infections were present in 72% of the ICU stays. Nine patients (33%) died in ICU and 3 others (11%) within 90 days of the last ICU discharge (vs. 15% during a 7.5±5 years period of follow-up in the control group, p < 0.0001). Risk-factors of ICU-admission. Three risk-factors independently associated with ICU-admission were highlighted: higher age at IM onset (62±13 vs. 53±13 years, p < 0.05), higher rate of chronic kidney failure (26% vs. 0%, p < 0.05) and higher incidence of arterial/venous thrombosis history (37% vs. 0%, p < 0.05). Other risk-factors identified only in univariate analysis included lower BMI (22.6±4.5 vs. 25.4±6.3), a history of interstitial lung disease (48% vs. 30%) and a higher Charlson comorbidity index (4.6±2.6 vs. 3.3±2). The type of IM was not significantly associated with ICU-admission, although no patient admitted in ICU had sIBM. It is noteworthy that cumulative number of immunomodulatory treatments in patients at the time of ICU-admission was lower than in the control group (0.5±0.7 vs. 1.9±0.8 p < 0.001).

**Conclusions:** IM-patients admitted in ICU frequently have recent onset and untreated active IM with respiratory failure. ICU-admission is associated with older age and a higher number of comorbidities. Mortality is high.
P97

Comparison of autoantibody specificities tested by a line blot
assay and immunoprecipitation-based algorithm in patients with
idiopathic inflammatory myopathies

Fabricio Espinosa-Ortega, Marie Holmqvist, Helene Alexanderson, Helena Storfors, Tsuneyo Mimori, Ingrid Lundberg, Johan Rönnelid
Karolinska University Hospital, Stokholm, Sweden

**Correspondence:** Fabricio Espinosa-Ortega

BMC Rheumatology 2019, **3**(Suppl 1):P97

To date, there is no standardized approach of myositis specific auto-
antibodies/Myositis associated autoantibodies (MSA/MAA) testing to be
used in clinical settings. Immunoprecipitation (IP) of RNA's with silver
staining and/or protein IP on cellular lysates is considered the gold
standard for most autoantibodies but is time-consuming, does not dif-
ferentiate antibodies targeting proteins with the same molecular
weight, and does not measure levels of autoantibodies and is not rou-
tinely available in clinical settings. Line blot assays (LB) represent a fas-
ter and semi-quantitative option to detect autoantibodies. Objectives
We aimed to compare the performance of a line blot (LB) and immuno-
precipitation (IP) assays and to describe clinical associations to autoanti-
body specificities in a cohort of patients classified as idiopathic
inflammatory myopathies (IIM). 119 patients were tested by a commer-
cial LB (Euroline Myositis Antigen Profile 4, Euroimmun, Germany) and
a combination of protein- and RNA- IP together with an anti-MDA5
ELISA. Agreement between assays was calculated by Cohen's kappa co-
efficient. Results The overall concordance was 76% with moderate
agreement (k:0.49). Agreement was very good for anti-SRP (k: 0.85) and
anti-Ku (k: 0.85), good for anti-Jo-1 (k: 0.69) and moderate for anti-
PmScl (k:0.58), anti-MDA5 (k:0.49), anti-TIF1gamma (0.57). Jo-1 LB+ IIM
had interstitial lung disease and arthritis compared to LB-negative (p <
0.001). Nineteen % of DM/PM patients were Jo-1+ compared to 0% of
IBM (p < 0.001). Anti-TIF1gamma+ patients had higher frequency of
DM skin rash than patients with other specificities (p = 0.003). LB-Mi-2+
was more common compared to IP+. Conclusion In conclusion, the
concordance rate between the two assays for detection of myositis
autoantibodies was moderate to very good for most prevalent specific-
ities. The LB assay seems to be valid and useful to identify subgroups
of IIM with specific clinical features.

P98

Situ Lymphocyte and Dendritic Cell Characterization in Idiopathic
Inflammatory Myopathies

Iazsmin Bauer Ventura, Daniel Reilly, Peter Pytel, Vladimir Liarski
University of Chicago, Chicago, USA

**Correspondence:** Vladimir Liarski

BMC Rheumatology 2019, **3**(Suppl 1):P98

Background/Purpose: The Idiopathic Inflammatory Myopathies (IIM) are the largest number of acquired and potentially treatable muscle disorders. Nevertheless, there are currently no FDA or EMA-approved medications apart from corticosteroids. We speculate the scarcity of effective therapeutics mirrors the lack of in-depth characterization of the immunopathogenesis of IIM. In this pilot study, we aim to apply previously validated approach of multi-channel confocal microscopy using fluorescent antibodies for identification and characterization of DC and lymphocytes populations in biopsies of patients with Dermatomyositis (DM) and Inclusion Body Myositis (IBM).
Methods: A total of 4 DM and 4 IBM samples were stained by myeloid dendritic cells (mDCs) with BDCA1 and CD11c; plasmacytoid DCs (pDCs) with BDCA 2 and CD123; cell nuclei with DAPI (Hoechst 33342), plasma cells with CD138, B-cells with CD20, T-helper lymphocytes with CD4, and cytotoxic T lymphocytes with CD8. These slides were imaged with the SP8 3D 3-color STED laser scanning confocal microscope. Regions of Interest (ROIs) of each biopsy were randomly acquired by means of tiling using a mechanized stage. The resulting image data was reviewed and manually analyzed for number of DCs and lymphocytes by a blinded observer (IBV) using Fiji Software. Mann-Whitney U test was used to calculate statistical significance for all analyses.

Results: IBM biopsies had larger proportions of plasma cells, cell counts means of 22 versus 8 per biopsy (p=0.003), CD4+ lymphocytes, 73 versus 38 cells (p=0.03), CD8+, 36 versus 10 cells (p=0.002) in comparison to DM biopsies. In respect to dendritic cells, double-positive staining for mDCs was also greater in IBM, cell count means of 8 versus 1 per biopsy (p=0.000). Moreover, IBM biopsies had higher counts of BDCA2 positive cells (p=0.008). Biopsies of DM and IBM were similar as for CD20 positive cells and double-positive pDCs. Conclusion: Our findings challenge the classic correlation between DM, IBM, pDCs, mDCs, and lymphocytes. Interestingly, we found a rich inflammatory milieu in IBM biopsies, with greater amounts of CD8 positive cells and mDCs, in concordance with the literature, but also of BDCA2, and CD4 positive cells. Other cell markers considered characteristic of DM, such as the pDC marker CD123 did not differ among the different diagnosis. This pilot study illustrates the complexity behind the cellular drives of IIM in regards to DCs. Priorly established patterns of inflammation used to describe these diseases must be revisited, as new therapeutic targets are urged in IIM.

P99

Performance of the new EULAR/ACR Classification Criteria for
Idiopathic Inflammatory Myopathies (IIM) in a Large Monocentric
IIM Cohort

Simone Barsotti¹, Valérie Leclaire², Antonella Notarnicola², Luise
Ekholm², Lara Dani², Maryam Dastmalchi², Ingrid E. Lundberg²
¹University of Pisa, Pisa, Italy; ²Karolinska University Hospital, Stockholm,
Sweden

**Correspondence:** Simone Barsotti

BMC Rheumatology 2019, **3**(Suppl 1):P99

Background/Purpose: Patients with IIM have been classified mainly according to Bohan and Peter (B&P) criteria, proposed in 1975. In 2017 the new EULAR/ACR criteria were proposed. They are able to classify patients with both adult/juvenile form of IIM and they are applicable also in patients with amyopathic DM (ADM) and in IBM even without the results of muscle biopsy. The objective of this study was to evaluate the performance of the new classification criteria for IIM in a large retrospective cohort of patients.

Methods: Consecutive patients with a clinical diagnosis of IIM, based on physician opinion, referred to a rheumatology unit from 1995 to 2018 were included and assessed according to the B&P and the EULAR/ACR criteria. Data were collected from an existing database and, when missing, additional variables were retrieved from the patient's records when available. Cohen's kappa (K) was used to measure the agreement between physician opinion and the classification criteria; in addition, sensitivity and specificity were calculated.

Results: A total of 439 patients were included in the analysis (M 157, F 282, mean age at the onset 53.5±17.5 years). In 18 patients at the onset were less than 18 years old. According to the physician opinion 214 patients had PM, 57 IBM, 57 DM, 12 Juvenile DM (JDM). 5 ADM. With the EULAR/ACR criteria 385 patients (sensitivity 87.7%), could be classified as IIM, 285 definite and 100 probable: 161 PM, 137 DM, 60 IBM, 14 ADM, 13 juvenile IIM. Applying the B&P criteria, 353 patients (sensitivity 80.4%) were classifiable as IIM (183 definite, 170 probable): 204 PM and 149 DM. The concordance between the two criteria (Cohen's K) was low (k=0.253 p=0.001). Fifty-four patients were not classifiable according to EULAR/ACR criteria (51 PM, 1 DM, 1 ADM, 1 JDM) and 86 with B&P criteria (55 PM, 19 DM, 8 IBM, 1 ADM and 3 JDM). Some patients with myositis specific autoantibodies were not classifiable (12 with EULAR/ACR, 30 with B&P). Missing detailed information on patterns of muscle weakness and some muscle biopsy features were explanations for not being able to classify most patients.

Conclusions: The new EULAR/ACR criteria performed well in a retro-
spective cohort using data from a myositis register and patient re-
cords from a myositis clinic, but they depend on muscle strength
testing of upper and lower extremities as well as of proximal and dis-
tal muscles in the legs.
P100

Tfh Cells in Human Myositis

Amrutesh Puranik¹, Mark Jensen¹, Yogita Ghodke-Puranik¹, Regine Tipon¹, Cynthia Loomis¹, Valerie Mezzano¹, Shanmugpriya Selvaraj¹, Theresa Wampler Muskardin¹, Lauren Pachman², Ann Reed³, Timothy Niewold¹

¹NYU School of Medicine, New York City, USA; ²Northwestern University, Evanston, USA; ³Duke University Medical Center, Durham, USA

**Correspondence:** Timothy Niewold

BMC Rheumatology 2019, 3(Suppl 1):P100

**Objectives:** T and B cells come together in ectopic lymphoid aggregates in myositis, suggesting that local T:B cell interactions could play a role in disease. T follicular helper cells are increased in circulation in patients with active myositis. We studied circulating Tfh cells from myositis patients using single cell RNA-sequencing, and examined the proximity of Tfh cells to B cells in patient biopsies.

**Methods:** Tfh cells were sorted from peripheral blood and subsets were identified by chemokine markers to designate Tfh1 and Tfh2/17 cell subsets. RNA sequencing was performed on individual cells, and data were analyzed using a pseudotemporal ordering strategy. Biopsies were stained using the OPAL standardized sequential immunofluorescence method for PD-1, CXCR5, CD19 and CD4 in human muscle, and machine learning was used to map proximity of B cells to all T-cells compared with Tfh cells.

**Results:** We found various subsets within the Tfh pool, corresponding to Tfh1 and Tfh2/17 cells and some cells that looked to be transitioning between states. Tfh2/17 were enriched in myositis patients vs. controls. The Tfh2/17 cells demonstrated an interferon signature, while the Tfh1 cells had a type II interferon and proteasome signature. In tissue, we could demonstrate Tfh cells in close proximity to B cells in lymphoid aggregates.

**Conclusion:** Tfh cells are present in myositis biopsies juxtaposed to B cells, suggesting productive T:B interactions in the tissue. Tfh subsets in blood from patients demonstrate distinct pathological signatures when compared to controls.

P101

Role of mitochondria in membrane repair and muscle weakness in myositis

Kanneboyina Nagaraju¹, Jessica Boehler², Adam Horn², James Novak², Ning Li¹, Svetlana Ghimbovschi², Ingrid Lundberg³, Helene Alexanderson³, Li Alemo-Munters³, Jyoti Jaiswal²

¹Binghamton University, Binghamton, USA; ²Children's National Health System, Washington, USA; ³Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Kanneboyina Nagaraju

BMC Rheumatology 2019, 3(Suppl 1):P101

**Objective:** Inflammatory myopathies are considered autoimmune disorders of muscle, but whether these diseases are mediated by the adaptive immune response or reflect the chronic inflammatory status of the diseased tissue itself is controversial. Immunosuppressive therapy shows variable efficacy in these patients, and there is little direct relationship between inflammation in muscle and the patient's degree of weakness and disability. We have hypothesized that muscle weakness and damage is partially independent of adaptive immune response but is dependent on the ability of functional mitochondria to not only provide ATP but also repair muscle membrane after injury.

**Methods:** We have performed mechanistic studies involving gene and protein expression analysis of innate immune (e.g., toll like receptor) and metabolic pathways (e.g., Harakari) as well as monitoring mitochondrial activity and cells response to injury. We also evaluated effects of a moderate exercise regime on the reversibility of innate immune and metabolic changes in PM and DM patients.

**Results:** We present a novel model to explain the relatively poor correlation between inflammation and weakness in myositis. This model arose from our work that demonstrated pro-apoptotic mitochondrial protein, Harakari (Hrk) that selectively interact with survival-promoting Bcl-2 and Bcl-X(L), is significantly upregulated in myositis patient

biopsies. This observation coupled with our recent studies that demonstrated functional mitochondria are essential not only for ATP generation but also for muscle membrane repair after injury. We found that primary muscle cells isolated from myositis patients showed increased Hrk expression and decreased mitochondrial activity and poor membrane repair after injury. We further confirmed that transient overexpression of Hrk in normal muscle cells lead to defective mitochondria and poor membrane repair that potentially lead to release of Danger Associated Molecular Patterns (DAMPs) as well as serum biomarkers such as creatine kinase in myositis patients. More importantly we found that TLR-7 signaling in skeletal muscle cells induce Hrk expression leading to a self sustaining loop in myositis muscle miroenvironment. We also show that moderate endurance exercise by myositis patients facilitates improved mitochondrial function by slowing disease progression through a reduction in HRK and TLR7 gene expression. This prevents the establishment of an HRK-TLR7 driven feed-forward loop that underlies pathogenesis of this disease

**Conclusion:** This model predicts that enhancing mitochondrial biogenesis and decreasing inflammatory cytokine signaling in skeletal muscle would improve muscle membrane repair and restore muscle strength in these patients.

P102

Features of repeated muscle biopsies and of phenotypes of monocytes in paired blood samples and clinical long-term response to treatment in patients with idiopathic inflammatory myopathy - a pilot study

Karina R. Gheorghe¹, Quan Tang¹, Xing-Mei Zhang¹, Eva Lindroos¹, Helene Alexanderson¹, Cecilia Wick¹, Mei Bruton¹, Robert A. Harris¹, Inger Nennesmo¹, Ingrid E. Lundberg¹

Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Karina R. Gheorghe

BMC Rheumatology 2019, 3(Suppl 1):P102

**Objective:** Idiopathic inflammatory myopathies (IIM) are systemic inflammatory disorders primarily affecting skeletal muscle. Persisting muscle weakness despite immunosuppressive treatment leads to loss of function and disability over time. In this pilot study we aimed to identify biomarkers in repeated muscle biopsies and paired blood samples, taken before and after conventional immunosuppressive therapy, in order to predict long-term therapeutic responses in patients with IIM.

**Methods:** 13 newly diagnosed IIM patients were selected from our myositis registry (SweMyoNet), comprising six responders and seven non-responders. Treatment response 3 years after diagnosis was defined by achieving at least minimal improvement according to ACR/EULAR 2016 improvement criteria, together with reaching MMT-8 ≥ 78/80. Muscle biopsies were available at baseline from all selected patients. Post-treatment muscle biopsies after a median of 11 months follow-up were available from 9 patients and paired PBMCs from 5 patients. Frozen biopsy sections were stained immunohistochemically for expression of CD3, CD66b, IL-15, CD68, CD163, Major histocompatibility class I (MHC 1) and myosin heavy chain neonatal (MHCn). PBMCs were analyzed by flow cytometry for monocyte phenotypes (CD14, CD16, CD68, CX3CR1, and CCR2).

**Results:** Before treatment there were no significant differences between responders and non-responders in any of the clinical or muscle biopsy variables or frequency of monocyte subsets. MMT-8 was significantly higher compared to baseline in the responders 1 year after initiation of treatment, and this improvement was maintained at 3-year follow-up. In responders at 3 year follow-up the expression of CD68 in the post-treatment biopsy was significantly lower compared to in non-responders (P < 0.05).

**Conclusions:** In this pilot study, baseline biopsy, monocyte profile or clinical data did not predict long-term treatment response, but in the post-treatment biopsy within 1 year of immunosuppressive treatment a lower number of macrophages (CD68+) predicted a more favorable long-term clinical response regarding to improved muscle strength and disease activity. This data indicates that repeated muscle biopsy may offer additional information to guide further treatment.
P103

**The Göttingen Interdisciplinary Immunological Case Conference (GIICC): multi-disciplinary collaboration for effective care pathways of patients with myositis**

Peter Korsten¹, Jan-Gerd Rademacher, Cornelia Seitz, Jana Zschüntzsch, Rotraud Mößner, Michael Zeisberg, Ulrike Olgemöller, Cordula Buck, Sabrina Zechel, Radovan Vasko, Jens Schmidt
Universitätsmedizin Göttingen, Göttingen, Germany

**Correspondence:** Peter Korsten

BMC Rheumatology 2019, 3(Suppl 1):P103

**Objectives:** Inflammatory myositis (IM) comprises polymyositis (PM), dermatomyositis (DM), necrotizing myositis (NM), overlap myositis (OM), and antisynthetase syndrome (ASS). At the University Medical Center Göttingen, a tertiary reference center for IM, we have established an interdisciplinary case conference for patients in need of a comprehensive and multispecialty assessment.

**Methods:** This is a single center, retrospective observational analysis of patients evaluated at the GIICC. GIICC has been established as a monthly interdisciplinary meeting with fixed members from the Departments of Nephrology and Rheumatology, Neurology, Pulmonary medicine, Neuropathology, and Dermatology. 1 to 2 attending physicians of each Department regularly attend the conference. Patients with IM can be scheduled for a comprehensive evaluation and data from medical records (history and physical examination, laboratory data, imaging, pathology) are assessed. Consensus is reached by face-to-face discussion of each patient. A report is generated in the general hospital documentation system. Patients can be allotted for additional diagnostic evaluation, change of treatment, or treatment recommendations ("second opinion") for primary or secondary care providers.

**Results:** The majority of patients is scheduled for additional diagnostic tests, either at the Department of Neurology or at the Department of Nephrology and Rheumatology. Most patients receive immunosuppressive therapies (second or third line treatments, such as immunosuppressants, IVIG and/or Rituximab) for interstitial lung disease or myositis. Many patients require rheumatologic evaluation for either presence or absence of arthritis, presence of an additional autoimmune disorder or specific diagnostic tests, such as nailfold video capillaroscopy, musculoskeletal ultrasound or MRI. Patients scheduled for neurologic evaluation mostly require re-evaluation of muscle histopathology, repeat EMG testing or additional imaging tests, including MRI of muscles and/or myosonography.

**Conclusions:** By evaluating patients with IM at the GIICC, our experience is that patients receive a comprehensive, interdisciplinary, high class expert evaluation in a timely manner and with a concrete diagnostic/treatment plan. Furthermore, patient care is harmonized between the respective Departments following a Standardized Operating Procedure. Based on our preliminary retrospective analysis, we plan to prospectively assess GIICC in the setting of a quality improvement study (QIS) following the recommendations of the EQUATOR network.

P104

**ACR/EULAR myositis classification 2017: "real world data" from the Göttingen cohort**

Kanan Hasanov, Sabrina Zechel, Rachel Zeng, Stefanie Glaubitz, Peter Korsten, Cornelia S. Seitz, Jens Schmidt
University Medical Center Göttingen, Göttingen, Germany

**Correspondence:** Kanan Hasanov

BMC Rheumatology 2019, 3(Suppl 1):P104

**Background:** The ACR/EULAR classification criteria for myositis have recently been published. They are based upon a large cohort of patients from databases, including the network of IMACS and the Euromyositis registry.

**Objective:** The aim of this study is to provide "real-world" data on the ACR/EULAR classification criteria for myositis by applying the criteria to our cohort of myositis patients at the University Medical Center Göttingen, Germany.

**Material and Methods:** In a retrospective fashion, 270 patients with myositis were included and IRB-approved informed consent was obtained. The patients were treated at the University Medical Center between 2009 and 2018 and had received the diagnosis polymyositis (PM), dermatomyositis (DM), necrotizing myopathy (NM), antisynthetase syndrome (ASS) or inclusion body myositis (IBM). The clinical records were assessed for all parameters required for assessment of the ACR/EULAR classification criteria.

**Results:** The score and diagnosis according to the ACR/EULAR classification is compared to all other major myositis classifications for PM and DM (Bohan & Peter, Tanimoto, Targoff, Dalakas, and Hoogendijk) and for IBM (Dalakas, Griggs, Rose). The data will evaluate the sensitivity and specificity by assessing the respective diagnosis for each of the classification criteria.

**Discussion:** This study may support the future use of the ACR/EULAR classification criteria for myositis by providing "real-world data" from a well characterized cohort. The data will be helpful for continued update of the classification criteria.

P105

**Incidence of Idiopathic Inflammatory Myopathies (IIM) in Adults in Fife, Scotland, UK**

John McLaren, Paul Allcoat, Michael Hearst, Elizabeth Furrie, Sarah Hailwood

NHS Fife, Kirkcaldy, UK

**Correspondence:** John McLaren

BMC Rheumatology 2019, 3(Suppl 1):P105

**Objectives:** To determine the Adult incidence of IIM in the Kingdom of Fife, Scotland. The Fife population is 370,000 and constitutes 6.8% of the Scottish Population (5,425,000). 98% of the Fife population is Caucasian. We also sought to characterise the incident IIM cases in terms of subtype and autoantibody profile.

**Methods:** All newly diagnosed Adult cases (≥ 18 years) of IIM between 01.03.17 and 30.11.18 were recorded (11.75 year period). The cases were identified by a search of the Fife Rheumatic Diseases Unit Database using IIM-specific ICD-10 codes. These were cross-referenced with a prospective personal database of IIM cases established by the Lead Author (JMCL) on 26.02.17. In addition a search of all Fife patients enrolled in the UKMYONET study was also performed. All patients with 'definite' or 'probable' IIM by the Bohan & Peter 1977 criteria: Clinically defined Inclusion Body Myositis (IBM) by the ENMC 2011 criteria; or other specific criteria in the case of Clinically Amyopathic Dermatomyositis (CADM) and Immune-mediated Necrotising myopathy (IMNM) were included.

**Results:** 53 newly diagnosed Adult IIM cases were identified. 11 Dermatomyositis (DM) (3 NXP2; 2 Jo-1; 2 TIF1-G; 1 Mi-2; 3 Myositis-specific antibody (MSA) not tested). 4 Polymositis (PM) (1 Jo-1; 1 MDA5; 1 MSA/Myositis-associated antibody (MAA) negative; 1 MSA not tested). 12 Anti-synthetase syndrome (8 Jo-1; 3 PL7; 1 PL12) and 3 patients with Jo-1 isolated Interstitial lung disease (ILD). 5 Overlap Connective tissue disease (CTD): 2 Systemic Lupus Erythematosus; 2 Systemic sclerosis; 1 Mixed CTD. 5 Cancer-associated myositis (CAM): 2 lung (1 NXP2 DM & 1 SRP PM); 1 ovarian (DM, MSA not tested); 1 Breast (DM, TIF1-G); 1 Prostate (DM, Mi-2). 5 CADM (2 MDA5; 1 TIF1-G; 1 NXP2; 1 MSA not tested). 4 IMNM (2 HMGCR; 1 HMGCR overlap with IBM; 1 SRP overlap with IBM who developed bladder cancer < 3 years after diagnosis). 4 sporadic IBM (2 cN-1A/Mup44 of which 1 overlap with Primary Sjogren's Syndrome; 2 MAA not tested).

**Conclusions:** The incidence of IIM in Fife, Scotland is 4.5 cases per year which equates to an annual incidence of 12.2 cases per million population. This is comparable with the incidence data published for
Salford in the UK (17.6). However the IIM subtypes differed from Salford in that Fife has a much lower incidence of PM. 40/49 (82%) of Fife patients who were tested were found to be MSA positive.

## P106

### Muscle inflammation and muscle weakness in mouse models of neuromuscular diseases

Amanda Mullen<fnref n="1" />, Joyce Rowsell<fnref n="1" />, Kitipong Uaesoontrachoon<fnref n="1" />, Alex MacKinnon<fnref n="1" />, Molly Praest<fnref n="1" />, Sadish Srinivassane<fnref n="1" />, William Ross<fnref n="1" />, Donika Shala<fnref n="1" />, Jordan Warford<fnref n="1" />, Eric Hoffman<fnref n="2" />, Kanneboyina Nagaraju<fnref n="2" />
¹AGADA Biosciences Inc, Halifax, Canada; ²Binghamton University, Binhamton, USA

**Correspondence:** Amanda Mullen

BMC Rheumatology 2019, **3**(Suppl 1):P106

**Objective:** It is generally perceived that excessive muscle inflammation may be responsible for causing muscle weakness in chronic inflammatory muscle diseases. Evaluation of muscle inflammation using qualitative/semi-quantitative histological (e.g., H&E) measures is not optimal in neuromuscular diseases because inflammation is often patchy. Therefore, we have developed a non-invasive quantitative measure of muscle inflammation in live mice using ProSense® 680, a cathepsin (macrophage) activatable fluorescent in vivo aging agent. Here we have tested the hypothesis that excess muscle inflammation is associated with more muscle weakness.

**Methods:** We have used male (age: 9-10 weeks) dystrophin deficient mdx (n=12) and normal control (n=8) mice to test this hypothesis. We measured muscle inflammation in the hind limbs of control and mdx mice using near-infrared fluorescent agent, Prosense680 on the IVIS Lumina III Imaging System. We also measured in vivo specific force of the tibialis anterior (TA) muscle on these mice using the Aurora Scientific 809C in-situ Mouse Apparatus. Both assessments were done in a blinded fashion.

**Results:** Mdx mice showed highly variable but significantly increased inflammation in hindlimbs in comparison to BL10 control mice. Median cathepsin activity measured as radiant efficiency units (REU) in Mdx mice is about 295% higher than control BL10 mice (mdx vs BL10: 4.07E8 vs 1.38E8 REU) suggesting macrophage infiltration in skeletal muscle. Mdx mice also showed lower specific force of the TA muscle in comparison to control BL10 mice. Median TA specific force in mdx mice is 60% lower than control BL10 mice (mdx vs BL10: 26.00 kN/m2 vs 43.20 kN/m2). Correlation of cathepsin activity with specific force of the TA muscle indicates that muscle inflammation is modestly correlated with muscle specific force (p=0.0007, r2 0.48).

**Conclusion:** We have developed a non-invasive quantitative measure of muscle inflammation that can be used longitudinally in live animals. We found a modest correlation between muscle inflammation and specific force suggesting other non-inflammatory factors may play a role in muscle weakness in dystrophin deficient mdx mice.

## P107

### National trends in Utilization of Emergency Department Services and Health Care Cost associated with Idiopathic Inflammatory Myopathy visits: An analysis of Nationwide Emergency Department Survey in USA, 2010-2014.

Umar Zahid<fnref n="1" />, Sunita Upreti<fnref n="1" />, Katherine Ellingson<fnref n="2" />, Lisa Christopher-Stine<fnref n="1" />

**Correspondence:** Umar Zahid; Lisa Christopher-Stine

BMC Rheumatology 2019, **3**(Suppl 1):P107

**Introduction:** Idiopathic inflammatory myopathies (IIMs) are a cluster of uncommon disorders. Most often these patients are on long term treatment and they tend to have frequent emergency department (ED) visits either with a disease flare or with complications from therapy. Data about the trend of ED utilization and health care burden of IIM patients is lacking. **Objective:** To estimate the IIMs related ED visits, disposition from ED, health care cost and the predictors of subsequent hospitalization.

**Methods:** We used the Nationwide Emergency Department Sample (NEDS) dataset. Chi-square and t-tests were used to test statistical significance of categorical and continuous variables respectively. Trend of IIM related visits from 2010-2014 was tested using Cochrane-Armitage-test. Additionally, predictors of hospital admission were assessed by running separate multivariable logistic regression model for each type of IIM (dermatomyositis (DM), polymyositis (PM) & inclusion body myositis (IBM)).

**Results:** A nationally weighted estimate of 82,241 ED visits with the diagnosis of IIMs (DM=37.8%, PM=54.0% & IBM=8.2%) were identified, that accounted for 0.12% of all ED visits from 2010 to 2014. Over the period of five years, an absolute increase of 20.8% DM related ED visits and 57% IBM related visits were observed (p=0.04) while PM related ED visits decreased 9.3% from 2010-2014. Median number of co-morbidities were increased in patients with IBM compared to PM and DM (IBM=12, PM=11, DM=10). Total national cost of IIM related visits increased by 62% from $6.97 million to $11.3 million from 2010 to 2014 (p < 0.05). Median cost was similar [IBM ($1857) PM ($1850) and DM ($1808)]. Overall 71% of all IIM related ED visits resulted in hospitalization; significant higher rates of hospitalization were noted in IBM patients. However, the rate of hospitalization after an IIM related ED visit decreased by 8% over the study time period. Median length of hospital stay in patients with IIM was 4 days. Among the patients hospitalized with IIM, 51% were discharged home, 24% were transferred to skilled nursing facility and 17% were send home with health care. Several demographic characteristics were found to be significantly associated with a higher odds of hospitalization in an adjusted multivariable regression model such as old age, male gender, geographic location and number of comorbidities.

**Conclusion:** ED services utilization and associated total costs are increasing over time for the patients with IIM. However, with the advancement in the treatment, rate of hospitalization and length of stay are significantly decreasing.

## P108

### The prevalence of p62 immunostaining in muscle biopsies from patients with myositis, non-inflammatory myopathies, and neurogenic disorders

José C. Milisenda³, Iago Pinal-Fernandez<fnref n="1" />, Thomas E. Lloyd<fnref n="2" />, Josep Maria Grau³, Andrea L. Corse<fnref n="1" />, Andrew L. Mammen<fnref n="1" />

**Objectives:** p62 is a marker of autophagy that has been proposed to be useful to diagnose patients with inclusion body myositis. The objective of this study was to assess the diagnostic utility of p62 by comparing the prevalence and pattern of p62 staining in muscle biopsies from patients with inclusion body myositis compared to other types of inflammatory and non-inflammatory myositis.

**Methods:** All patients from the Johns Hopkins Myositis Center longitudinal cohort from August 2013 to January 2017 with an available muscle biopsy and p62 immunostaining were included in the study. p62 immunostaining was classified as negative if all muscle fibers were negative, and positive if any of the six patterns described in Figure 1 was present. All biopsies were reviewed by an experienced myopathologist who was not blinded for clinical information and by a myology specialist who was masked to disease activity and subgroup.

**Results:** 399 muscle biopsies with p62 immunostaining were available for the study. 136 muscle biopsies were from patients with myositis including 37 with IBM, 40 with DM, 31 with immune-mediated necrotizing myopathy [IMNM] and 28 with PM patients. The rest were from patients with other myopathies (n=53), neurogenic disorders (n=85), normal biopsies (n=29) and biopsies with an undefined diagnosis (n=96). The proportion of p62 positive cases were 67.6% in the myositis group and 0% in those with normal biopsies. p62 staining was most

<footnote n="1">¹Johns Hopkins University School of Medicine, Baltimore, USA;</footnote>

<footnote n="2">²University of Arizona, Tucson, USA</footnote>

<footnote n="1">¹National Institutes of Health, Bethesda, USA; ²Johns Hopkins University School of Medicine, Baltimore, USA; ³Hospital Clínic de Barcelona, Barcelona, Spain</footnote>

<footnote>**Correspondence:** José C. Milisenda; Iago Pinal-Fernandez</footnote>

<footnote>BMC Rheumatology 2019, **3**(Suppl 1):P108</footnote>
prevalent in IBM (92%), IMNM (87%), and dermatomyositis (57%) muscle biopsies (all "p < 0.001") but uncommon in PM (29%) and in other types of myositis (all < 31%). Except for the perivacuolar pattern (19%, "p < 0.001"), IBM was not associated with any characteristic distribution of p62 staining (Table 1).

Conclusion: p62 immunostaining is not specific for IBM and is also common in IMNM and DM muscle biopsies.

## P109

### The spectrum of idiopathic inflammatory myopathy in a multi-ethnic Malaysian population

Khean Jin Goh, Tomica Ambang, Cheng Yin Tan, Jasmin Raja, Kum Thong Wong

University of Malaya, Kuala Lumpur, Malaysia

Correspondence: Khean Jin Goh

BMC Rheumatology 2019, **3**(Suppl 1):P109

**Objectives:** To describe the spectrum of inflammatory myopathy in a multiethnic Asian population.

**Methods:** Patients whose muscle biopsy was diagnosed as inflammatory myopathy at the Pathology Department, University of Malaya between 1995 and 2016 were reviewed. Clinical data and muscle pathology were retrospectively reviewed and re-classified according to the European Neuromuscular Center (ENMC) criteria. Biopsies diagnosed as polymyositis (PM) or nonspecific myositis were specifically reviewed by a muscle pathologist and re-classified if necessary. Serological studies were carried out in some cases only. Inclusion body myositis (IBM) was classified according to the ENMC IBM diagnostic criteria. Overlap myositis is there was associated connective tissue disease and myositis associated with antisynthetase syndrome (ASS) were diagnosed if there were positive antisynthetase antibodies or if there were additional compatible clinical features such as interstitial lung disease, Raynaud phenomenon or mechanics hands.

**Results:** There were 338 patients, 221 (65.4%) were female. Ethnic groups included 165 (48.8%) Chinese, 118 (34.9%) Malays, 46 (13.6%) Indians and 9 (2.7%) other ethnicities, reflecting the ethnic breakdown in urban Malaysia. 138 (40.8%) were dermatomyositis (DM) (63 (42.7%) juvenile DM (JDM) and 75 (57.2%) adult DM); 80 (23.7%) immune-mediated necrotizing myopathy (IMNM); 37 (10.9%) PM; 33 (9.8%) overlap myositis (including 6 with ASS) and 19 (5.6%) were IBM. A further 32 (9.5%) were classified as nonspecific myositis. Mean age and range for myositis subgroups were 7.7 years (1-17) (JDM), 49 (20-80) (adult DM), 40.4 (6-80) (IMNM), 49.6 (17-79) (PM), 61.2 (40-79) (IBM) and 37.2 (8-61) (overlap myositis). There were more women in all subtypes except IBM where 63.2% were men. All subtypes had more ethnic Chinese-Malaysian patients except JDM and overlap myositis in which there were more ethnic Malays. Of 36 IMNM patients with serological testing, 16 (44.4%) were positive for anti SRP antibody, six (16.7%) were anti HMGCR antibody and two were positive for both antibodies. 12 (33.3%) were negative for both antibodies. In 6 patients with ASS, anti Jo1 was positive in 5 patients and anti PL7 was positive in one. There were 8 (2.4%) malignancies, 7 (11.1%) adult DM and 1 nonspecific myositis.

**Conclusions:** Common inflammatory myopathy subtypes are dermatomyositis and immune-mediated necrotizing myopathy. IBM is seen Malaysians but in a lower proportion of cases. The subtypes and demographic characteristics of inflammatory myopathy in Malaysians are similar to other populations.

## P110

### The role of Muscle Biopsy Score in Assessing Disease Activity in Adult Patients with Idiopathic Inflammatory Myopathies

Lining Zhang, Xin Lu, Xiaolan Tian, Xiaoxiao. Zheng
China-Japan Friendship Hospital, Beijing, China

Correspondence: Lining Zhang

BMC Rheumatology 2019, **3**(Suppl 1):P110

**Objective:** The aim of this study was to investigate the role of muscle biopsy score in relation to the disease activity of idiopathic inflammatory myopathy(IIM) in Chinese adult patients.

**Methods:** Total 423 adult IIM patients in China-Japan Friendship Hospital from December 2008 to June 2017 were included in this study. The score of disease activity was assessed using IMACS Core Set Measures of IIM. The muscle biopsy specimens of IIM patients were performed by immunohistochemical staining of MHC-I, CD3 and CD20 molecules. Furthermore, the muscle biopsy score of each specimens was measured separately by four parts of muscle tissue including muscle fiber, inflammation infiltrating, blood vessel and connective tissue.

**Results:** The degree of muscle biopsy score was associated with the overall disease activity (r=0.228, P< 0.05), the increase of muscle activity(VAS)(r=0.407, P< 0.05) and creatine kinase(CK) levels (r=0.466, P< 0.05) of IIM patients, respectively. Moreover, among untreated patients, the muscle VAS of dermatomyositis(DM) were positive correlated to the muscle biopsy total score, the score of muscle fiber and inflammation infiltrating of muscle tissue(r=0.30, 0.312 and 0.241, P< 0.05) respectively. While, the high score of muscle fiber was related to the disease activity of polymyositis(PM) patients (r=0.478, P< 0.05). When analyzed according to different myothitis specific antibodies(MSAs) groups among initial untreated patients,including anti-TIF-1 antibody,anti-NXP-2 antibody,anti-Mi-2 antibody,anti-MDA-5 antibody,anti-Jo-1 antibody,non Jo-1 anti-synthetase antibody,anti-SRP antibody,anti-HMGCR antibody,and antibody-negative bodies,we found that patients with anti-SRP or anti-HMGCR autoantibodies showed high correlation between MB score with muscle activity(-VAS)(r=0.933 and 0.975,P< 0.05),which showed no significant correlations in other autoantibody subgroups.

**Conclusion:** The increased muscle biopsy score, including muscle fiber and inflammation infiltrating score in muscle tissue are related to the disease activity of PM and the CK levels of DM, as well as in some of the MSAs positive subgroups. The measures of muscle biopsy score can be used as an effective tool to evaluate the disease activity of IIM.

## P111

### Hsp90 is increased in plasma and muscle tissue in idiopathic inflammatory myopathies and correlates with disease activity and skeletal muscle involvement

Hana Storkanova¹, Sabina Oreska¹, Maja Spiritovic², Barbora Hermankova², Olga Krystufkova¹, Herman Mann¹, Karel Pavelka¹, Jiri Vencovsky¹, Ladislav Senolt¹, Michal. Tomcik¹

¹Institute of Rheumatology, Prague, Czech Republic; ²Charles University, Prague, Czech Republic

Correspondence: Hana Storkanova

BMC Rheumatology 2019, **3**(Suppl 1):P111

**Objectives:** Heat shock proteins (Hsps) are chaperones playing important roles in skeletal muscle physiology, adaptation to exercise or stress, and activation of inflammatory cells. The aim of our study was to assess Hsp90 expression in muscle biopsies and plasma of patients with idiopathic inflammatory myopathies (IIM) and to characterize its association with IIM-related features.

**Methods:** Total of 277 patients with IIM (198 females, 79 males; mean age 54.8; disease duration 4.1 years; dermatomyositis (DM, 104)/polymyositis (PM, 104)/cancer associated myositis (CAM, 42)/ necrotizing myopathy (IMNM, 27)) and 100 age-/sex-matched healthy individuals were included in plasma analysis and 50 muscle biopsy samples were stained for Hsp90 (PM-10, DM-10, IMNM-10, myodystrophy-10, myasthenia gravis-10). Patients with PM/DM fulfilled Bohan and Peter criteria and CAM was defined as cancer within 3 years of IIM diagnosis. Plasma Hsp90 was measured by ELISA kit (eBioscience, Vienna, Austria). Data are presented as median.

**Results:** In muscle biopsies Hsp90 expression was higher in IIM than in myodystrophy (myasthenia gravis used as another control was
negative). Increased Hsp90 was detected in perifascicular degenerat-
ing and regenerating fibers, inflammatory cells (DM, PM), and nec-
rotic and regenerating fibers (IMNM). Plasma Hsp90 levels were
increased in IIM patients compared to healthy controls (20.2 vs. 9.2
ng/mL, p < 0.0001), and in individual subgroups of IIM vs. healthy
controls (PM: 19.4, DM: 22.4, CAM: 19.1, IMNM: 19.6 ng/mL, p <
0.0001 for all). Hsp90 levels in all patients positively correlated with
LD and AST (r=0.551, p < 0.0001; r=0.372, p < 0.0001, respectively),
and there was a trend towards correlation with CK (r=0.111, p=
0.068). Increased Hsp90 was associated with decreased MMT-8 values
(r=-0.136, p=0.029), in particular in proximal muscles. Hsp90 posi-
tively correlated with patient- and doctor- evaluated disease activity
(r=0.222, p=0.0004; r=0.217, p=0.0005, respectively), pulmonary and
muscle disease activity (r=0.201, p=0.001; r=0.146, p=0.018, respect-
ively), MITAX and MYOACT (r=0.175, p=0.005; r=0.159, p=0.012, re-
spectively), and with MDI extent/severity (r=0.215, p=0.003; r=0.120,
p=0.041, respectively). Higher Hsp90 was found in patients with
interstitial lung disease, cardiac involvement and dysphagia (25.4 vs.
18.9, p=0.004; 27.5 vs. 19.3, p=0.004; 25.0 vs. 18.2 ng/mL, p=0.018,
respectively).

Conclusions: We demonstrate increased Hsp90 expression in IIM muscle biopsy samples, specifically in inflammatory cells, degenerat- ing, regenerating and/or necrotic fibers. Increased Hsp90 plasma levels in IIM patients are associated with disease activity and dam- age, and with the involvement of proximal skeletal muscles, heart and lungs. Acknowledgement: Supported by AZV-16-33542A, MHC R 023728, and SVV - 260373.

P112

A high prevalence of conformational epitopes in patients with anti-TIF1γ limits the utility of solid-phase immunoassays as a detection method

Sarah Tansley, Zoe Betteridge, Hector Chinoy, Lucy Wedderburn, Neil McHugh

Royal National Hospital for Rheumatic Diseases, Bath, UK

Correspondence: Sarah Tansley

BMC Rheumatology 2019, **3**(Suppl 1):P112

Objectives: Autoantibodies targeting TIF1γ form the most common serological sub-group of patients with juvenile-onset myositis, and are clinically important in adult onset disease where they are strongly associated with malignancy. The desire for non-specialist, high throughput laboratory systems to detect myositis autoantibodies has delivered a range of immunoassays to detect key myositis autoantibodies, including anti-TIF1γ. Conformational epitopes are known to occur in a number of autoimmune diseases and have also been described with anti-TIF1γ. We aimed to determine whether conformational epitopes impacted on the sensitivity of different immunoassays.

Methods: We had previously determined the autoantibody status of over 3,000 patients with myositis using radioimmunoprecipitation. Anti-TIF1γ positive samples (determined by the presence of a 155/140kDa band on immunoprecipitation) were selected for further analysis by ELISA using recombinant TIF1γ (159 samples analysed, 72 juvenile-onset) and a commercially available lineblot (Euroimmun) (102 samples analysed, 53 juvenile-onset). Reverse immunoprecipitation blotting was performed using either monoclonal anti-TIF1γ(Sigma) or patient sera to confirm the presence of anti-TIF1γ in ELISA and lineblot negative sera.

Results: Using the immunoprecipitation result as a reference, 125/159 (79%) anti-TIF1γ positive samples were also positive by ELISA. Lineblot was less sensitive and only 59/102 (58%) of samples tested were positive. There was no difference in sensitivity between those with adult and juvenile-onset disease. Only two samples negative by ELISA (14%) were positive by lineblot, and both were weak positives. Sixteen of the ELISA and lineblot negative samples were further analysed by reverse immunoprecipitation blotting: 11/16 (69%) were positive, confirming the presence of autoantibodies targeting TIF1γ. Five (83%) of 6 adult patients with confirmed anti-TIF1γ and a known history of malignancy were positive by ELISA and 4 (66%) by lineblot.

Conclusions: In our cohort, ELISA was a more sensitive method for de-
tecting anti-TIF1γ than lineblot, but both methods can fail to identify
anti-TIF1γ in patients with malignancy. Approximately 1 in 5 myositis
patients with anti-TIF1γ determined by immunoprecipitation had a
negative result by ELISA but over a third were negative using a com-
mercially available lineblot. In most patients with a 155/140kDa band
on immunoprecipitation who test negative for anti-TIF1γ by ELISA and
lineblot, anti-TIF1γ can be confirmed by reverse immunoprecipitation
blotting. This suggests the presence of a conformational epitope. Alter-
native methodologies should be considered to enable sensitive, high-
throughput testing for this clinically important autoantibody.

P113

Towards disentangling the genetics of myositis: the DISSECT project experience

Matteo Bianchi¹, Antonella Notarnicola², The Dissect Consortium, Louise Pyndt Diederichsen³, Øyvind Molberg⁴, Hector Chinoy⁵, Janine Lamb⁵, Lars Rönnblom¹, Kerstin Lindblad-Toh¹, Ingrid E. Lundberg²

¹Uppsala University, Uppsala, Sweden; ²Karolinska Institutet, Stockholm, Sweden; ³Odense University Hospital, Odense, Denmark; ⁴University of Oslo, Oslo, Norway; ⁵University of Manchester, Manchester, UK

**Correspondence:** Matteo Bianchi

BMC Rheumatology 2019, **3**(Suppl 1):P113

Objectives: The DISSECT project is a northern European multidisciplin-
ary framework aiming at disentangling the genetics of myositis and
other inflammatory autoimmune diseases, all sharing the type I inter-
feron signature. Within this collaborative project, the main objectives of
the myositis working-group have been the following: • To collect de-
tailed clinical and serological information, as well as generate targeted
resequencing data from northern European myositis patients and
healthy controls. • To establish a database and a user-friendly analytical
platform that will provide a foundation for our myositis research pro-
jects. • To dissect the genetic components underlying myositis and its
disease mechanisms.

Methods: Detailed clinical and demographic data, as well as biological specimens and serological measurements for myositis-characterizing auto-antibodies have been obtained for 560 Scandinavian myositis patients (Sweden, Denmark, Norway) and 424 patients from Great Britain. The majority of the cases presented either with polymyositis or dermatomyositis. Additionally, healthy controls matched for population ancestry were sampled (1,319 from Sweden and Norway) or relevant data retrieved from publicly available repositories (1,812 British controls). We performed targeted resequencing of 1,853 genes involved in immune function and autoimmunity in all the sampled myositis patients and controls. Targets included coding sequences, full untranslated regions and conserved intronic and intergenic regions. After preliminary bioinformatic analysis, all the processed and quality-controlled genetic data, as well as the individual metadata, were uploaded and now constitute the core of the database together with several tailored statistical genetic tools for downstream analyses.

Results: After resequencing (targeting 32 Megabases, ~40x coverage), genetic imputation and subsequent quality control, both the Scandinavian and the British datasets comprise more than 500,000 high quality variants. Despite experiencing issues with harmonizing the analysis in different cohorts and with using out-of-study sample-sets, single variant and aggregate case-control association tests, as well as meta-analysis are being performed in order to confirm known and unravel novel loci associated with myositis. For example, the human leucocyte antigen locus shows a statistically significant association (p-value < 1x10-16) with myositis in both cohorts. Moreover, cases are being stratified according to their serological status and evaluated for any association with genetic variants with polymyositis and dermatomyositis.

Conclusion: We expect that our study will ultimately enable to improve
diagnostics and targeted treatments by finding disease variants likely
to be causative in the studied populations, thus promoting precision
therapy for myositis. Moreover, the establishment of the DISSECT myo-
sitis research database will facilitate future collaborative studies on
myositis.
P114

**Predictive factors for treatment response for patients with
idiopathic inflammatory myopathies a registry-based cohort**

Hector Fabricio Espinosa-Ortega, Marie Holmqvist, Maryam Dastmalchi,
Ingrid E. Lundberg, Helene Alexanderson
Karolinska University Hospital, Stockholm, Sweden

**Correspondence:** Hector Fabricio Espinosa-Ortega

BMC Rheumatology 2019, **3**(Suppl 1):P114

**Objectives:** The aim of this study was to test the usefulness of auto-
antibodies and clinical features as predictors for response to im-
munosuppressive therapy after one year in with patients with
idiopathic inflammatory myopathies followed longitudinally in an
electronic myositis registry used in health care.

**Methods:** Patients identified in the SweMyoNet registry between January 1st, 2003 and December 31st, 2015 within 12 months of diagnosis were included. Patients with inclusion body myositis were excluded. The follow-up period ended at the closest visit to one year after start of treatment when response to therapy was assessed. Treatment of the individual patient was based on the treating physician's decision. Patients were categorized serologically by the presence of 1) any antisynthetase autoantibody, 2) non-antisynthetase autoantibody, 3) any myositis associated antibody, and 4) negative to any of these. The ACR/EULAR 2016 criteria for Clinical Response were applied to measure response, and it was categorized in minimal (20-39/100), moderate (40 59/100) and major (>60/100) response. We tested the association between serological groups and other predictors with every category of response by logistic regression modelling.

**Results:** 179 patients were identified. Mean age at inclusion was 57 years (±14), 65% were female. 59 (33%) patients had dermatomyositis, 81 (45%) polymyositis and 39 (22%) overlap myositis. 136 patients (77%) were positive to any autoantibody, 49% of these (n=67) were positive to myositis specific antibodies. 91% were given glucocorticoid treatment, 72% immunosuppressive drugs, 22% cyclophosphamide and 13% a biological drug. 111 of the 179 patients (62%) met the criteria for minimal response, 68 (38%) for moderate response and 32 (18%) for major response. We found no difference between the autoantibody defined subgroups and each of the categories of response. When we analysed time of first symptoms to diagnosis and glucocorticoid dose at baseline, we found that each month of delay from first symptoms to diagnosis was negatively associated with a decrease of 13% in the odds to achieve major response (OR 0.87, 95%CI 0.79-0.99) and an increase of 1mg of glucocorticoid at baseline was independently associated to 4% and 3% in the odds to achieve minimal and moderate response, respectively (OR 1.04 95%CI 1.02-1.06; 1.03 95% CI 1.01-1.05).

**Conclusions:** A shorter time span from first symptoms to diagnosis and more intensive initial immunosuppressive treatment were independently associated to higher rates of clinical improvement after one year with pharmacological treatment.

P115

**Muscle ultrasound in patients with Inclusion Body Myositis:
differentiating from mimics**

Kristofoor Leeuwenberg¹, Lisa Christopher-Stine², Julie Paik², Eleni Tiniakou², Nens van Alfen¹, Jonne Doorduin¹, Christiaan Saris¹, Jemima Albayda²

¹Radboud University, Nijmegen, Netherlands; ²Johns Hopkins University School of Medicine, Baltimore, USA

**Correspondence:** Kristofoor Leeuwenberg

BMC Rheumatology 2019, **3**(Suppl 1):P115

**Objectives:** Inclusion Body Myositis (IBM) is the most common inflammatory myopathy in individuals over the age of 50 years. When typical features of IBM are missing, its presentation can easily be confused with other forms of myositis or neuromuscular disorders. Recent studies have shown that muscle ultrasound (US) has the potential to differentiate between IBM and its mimicking diseases. In this study we aimed to further evaluate the ability of US to differentiate between IBM and Polymyositis/Dermatomyositis (PM/DM) and neuromuscular disorders using two separate cohorts.

**Methods:** Patients were included from two centers: the Johns Hopkins Myositis Center and the Muscle Center Radboudumc. We compared echo intensity and muscle thickness of the flexor digitorum profundus (FDP), gastrocnemius, rectus femoris and vastus lateralis muscles in patients with IBM (n = 41), PM/DM (n = 37), other neuromuscular disorders (n = 11) and healthy controls (n = 88). All patients with IBM, PM and DM met the EULAR/ACR classification criteria for each disease. The neuromuscular disorders consisted of five myopathies, four motor neuron diseases (ALS or PSMA), one polyneuropathy and one Lambert Eaton myasthenic syndrome.

**Results:** Echo intensity was higher and muscle thickness lower in all four muscles in IBM compared to PM/DM. When comparing IBM to the neuromuscular disorders, only the FDP showed a significantly higher echo intensity in IBM. The vastus lateralis was the only muscle with a significantly lower muscle thickness than the neuromuscular disorders. When evaluating the diagnostic potential per muscle group, logistic regression models using both ultrasound parameters showed that the FDP and vastus lateralis were the most discriminatory for IBM. However, the FDP proved to be the best candidate with a mean sensitivity/specificity of 94,9%/78,9% versus PM/DM and 93,8%/70,0% versus other neuromuscular disorders.

**Conclusion:** Among several characteristically involved muscles, the FDP and quadriceps muscles are the most discriminating for IBM on US when comparing to mimicking diseases (other myositis and neuromuscular controls). This may have value as a diagnostic tool for IBM.

P116

**Quantitative Strength Profiling in Inclusion Body Myositis: Faster Deterioration in Males and Positive Associations with Functional Assessment Tools**

James Lilleker¹, Alexander Oldroyd¹, Hector Chinoy¹, James Miller²

¹University of Manchester, Manchester, UK; ²Royal Victoria Infirmary, Tyne, UK

**Correspondence:** James Lilleker

BMC Rheumatology 2019, **3**(Suppl 1):P116

**Background:** Inclusion body myositis (IBM) is a rare idiopathic inflammatory myopathy subtype. Previous observational research has been limited to short-term studies. Detailed characterisation of the progression of muscle weakness is essential for clinical prognostication and delineating research end-points. Our study aimed to describe the disease progression rate in IBM using measures of muscle strength and functional assessment tools.

**Methods:** We performed a retrospective analysis of quantitative muscle strength data (six upper-limb and five lower-limb muscle groups using a CITEC dynamometer) and functional assessment tool results (IBM Functional Rating Scale [IBM-FRS] and the Neuromuscular Symptom and Disability Score [NSS]), systematically collected from verified IBM cases between July 2003 and March 2015 at a single UK neuromuscular clinic. Yearly rate of strength change was estimated for each muscle group and associations between strength and the IBM-FRS / NSS were examined using simple linear regression.

**Results:** Data from 80 IBM cases (44% female) were analysed, a total of 232 person-years and a median 2.3 years (IQR 0.6, 4.4) follow-up. Median age at IBM diagnosis was 68.4 years (62.4, 74.3). 4,760 strength measurements, 357 NSS measurements and 127 IBM-FRS measurements were performed. Similar rates of deterioration were found for right and left sided muscle groups. Annual rate of strength loss was greatest for grip, pinch and knee extension (-5.5% [95% CI -6.3, -4.6], -16.0% [-18.4, -13.5] and -7.1% [-7.6, -6.5] respectively). The rate of strength loss was greatest for the male cohort. Increased strength measurements were associated with improved IBM-FRS / NSS scores for most muscle groups tested.

**Conclusion:** This is the first long-term study to comprehensively demonstrate quantitative strength change in a large IBM cohort. Strength reduction occurred more rapidly in the male population. Our study provides valuable natural history data to support discussions regarding prognosis, will focus effective choice of outcome measures and inform study numbers for adequate statistical power in future clinical trials.
P117

**Application of electrical impedance myography (EIM) as a potential biomarker of Inclusion Body Myositis (IBM): A pilot study**

Bhaskar Roy¹, Seward B. Rutkove², Richard J. Nowak¹

¹Yale School of Medicine, New Haven, USA; ²Beth Israel Deaconess Medical Center, Boston, USA

**Correspondence:** Bhaskar Roy

BMC Rheumatology 2019, **3**(Suppl 1):P117

**Objective:** To assess muscle impedance parameters as potential biomarker of inclusion body myositis (IBM).

**Background:** There is an unmet need for an objective, easily applicable biomarker to assess IBM disease severity. Electrical impedance myography (EIM), a noninvasive technique, has shown promise as a potential biomarker in several neuromuscular disorders. This pilot study is evaluating the potential of EIM as a biomarker of IBM (clinicaltrials.gov || NCT03633318).

**Design/Methods:** We intend to recruit 20 patients with clinicopathologically confirmed IBM and 12 healthy controls. We present a preliminary analysis of 5 IBM patients (4 men, 1 woman; mean age 66 years) enrolled since August 2018. Healthy control data was not yet available to analyze. Each subject went through manual muscle testing (MMT) in neck flexion/extension, and 15 extremity muscles on both sides (maximum MRC score of 160), 6-minute walk (6MW), handgrip dynamometry, IBM-functional rating scale (IBM-FRS), and EIM measurements of deltoid, biceps, forearm flexors, rectus femoris, tibialis anterior, and medial gastrocnemius. Spearman rank correlation was used.

**Results:** Mean ± SD of MMT, grip strength (kg; Right/Left), IBM-FRS, 6MW (feet) were 130.75/160 ± 15, 9.8 ± 5/8.4 ± 5.4, 28.6 ± 7, and 1187 ± 480 respectively. A strong correlation was noted between averaged EIM-50 kHz and averaged ratio of EIM 200 kHz/50 kHz (EIM-200/50) from six muscles with IBM-FRS and 6MW distance (absolute rho ≥ 0.9, p-value ≤ 0.001). Hand grip strength showed moderate correlation with EIM-50 kHz from forearm muscles: rho 0.66, p-value 0.037. At individual muscle level, a moderate correlation was noted between EIM-50 kHz, EIM-200/50 and the weak muscles; rho values 0.58, -0.59 respectively with p-values < 0.001.

**Conclusion:** Preliminary results suggest that EIM may be a potential IBM biomarker and useful clinical trial outcome measure. These results should be interpreted carefully given the small sample size to date and further validation studies required. Our study remains open to enrollment with additional data available for presentation forthcoming.

P118

**Clinical description of familial inclusion body myositis and molecular genetic analysis**

Akatsuki Kubota¹, Hiroyuki Ishiura¹, Jun Mitsui¹, Jun Shimizu¹, Shoji Tsuji², Tatsushi Toda¹

¹University of Tokyo, Tokyo, Japan; ²International University of Health and Welfare, Otawara, Japan

**Correspondence:** Akatsuki Kubota

BMC Rheumatology 2019, **3**(Suppl 1):P118

**Objective:** Inclusion body myositis (IBM) is a chronic progressive myopathy with inflammatory and degenerative features, and its cause remains unknown. IBM is generally considered as a sporadic disease, but there are rarely familial cases. Here, we report a familial case of IBM.

**Methods:** The proband and his cousin suffered from middle-age onset, chronic progressive muscle weakness. Both patients were examined, and histopathological analysis of biopsied muscle specimens was performed. DNA samples were collected from the two IBM patients, and two healthy brothers of the proband. Given the pedigree tree, assuming X-linked inheritance, we conducted single nucleotide polymorphism (SNP) genotyping of the pedigree members.

**Results:** Both patients showed characteristic finger flexor weakness with moderately increased serum creatine kinase levels. Muscle biopsy showed cytotoxic T cells surrounding and sometimes invading non-necrotic myofibers, and inclusion bodies. These findings lead to

diagnosis of clinicopathologically defined IBM for both patients. SNP typing showed that approximately 1.1Mb at Xp22 were shared exclusively by the two patients.

**Conclusions:** Further genetic analysis is needed to explore the causative gene for familial IBM.

P119

**DMF diminishes inflammatory response in muscle cells**

Karsten Schmidt, Alice Faust, Simranjeet Kaur, Peter Balcarek, Jens Schmidt

Universitätsmedizin Göttingen, Göttingen, Germany

**Correspondence:** Karsten Schmidt¹

BMC Rheumatology 2019, **3**(Suppl 1):P119

**Objective:** This study aims to evaluate the effect of dimethylfumarate (DMF) in in vitro and in vivo model systems for inclusion body myositis (IBM). **Background:** The pathogenesis of IBM is caused by degenerative and inflammatory mechanisms. Various immunosuppressive therapies have failed to show a significant beneficial effect in clinical studies. DMF is an anti-inflammatory drug used in multiple sclerosis and psoriasis. It is known to diminish the cellular stress response to proinflammatory stimuli through activation and nuclear translocation of NRF-2.

**Methods:** The effect of DMF was studied in vitro in a well-established proinflammatory cell culture model system originated from a myoblast cell line and cultured primary muscle cells on RNA and protein level using quantitative PCR, immunocytochemistry and western blotting. For in vivo studies a previous characterized double-transgenic mouse strain (APP/PS1) was used. The mice were challenged with a proinflammatory stimulus via injection of LPS in the calf. Quantitative PCR, immunohistochemistry, FACS-analysis were performed to evaluate the effect of DMF on NRF-2 expression and translocation on cell stress and inflammatory response.

**Results:** In cell culture we found that DMF led to an upregulation and nuclear translocation of NRF-2 in rhabdomyosarcoma cells. Furthermore, DMF diminishes the inflammatory changes in the mouse model of IBM (APP/PS1 transgenic mice) after intramuscular injection with LPS. However, expression analysis revealed partly unaltered pro-inflammatory cytokines in DMF treated mice compared to non-treated, suggesting a rather focused therapy effect than an overall immunosuppressive effect.

**Conclusion:** We are able to show a molecular effect of DMF in muscle cells by translocation of NRF-2 and upregulation of associated genes. Secondly, we could show a significant reduction of inflammation under treatment with DMF in double-transgenic mice (APP/PS1) injected intramuscular with LPS.

P120

**Nonspecific pattern of muscular cN-1A expression in inclusion body myositis**

Anke Rietveld, Thomas Oosterhof, Saskia Lassche, Baziel van Engelen, Benno Küsters, Christiaan Saris, Ger Pruijn Radboud University, Nijmegen, Netherlands

**Correspondence:** Anke Rietveld

BMC Rheumatology 2019, **3**(Suppl 1):P120

**Objective:** Inclusion body myositis (IBM) is a slowly progressive acquired myopathy with inflammatory and myodegenerative features. Autoantibodies against cytosolic 5'-nucleotidase (cN-1A) are present in 33-76% of IBM patients. We investigated the pattern of cN-1A expression in healthy and diseased muscle tissue to gain more insight in the mechanisms that result in anti-cN-1A autoreactivity in IBM.

**Methods:** cN-1A was visualized in muscle tissue of IBM patients by immunohistochemical and immunofluorescent staining. Healthy individuals and patients with facioscapulohumeral dystrophy and oculopharyngeal muscular dystrophy were used as controls (n = 8 in each group). cN-1A expression was semi-quantitatively compared between these groups and related to other histopathological features such as COX-negativity and inflammatory changes.
Results: Immunohistochemical cN-1A staining showed predominant cN-1A expression in type 2 myofibers in all groups. Regenerating fibers occasionally showed cN-1A expression, irrespective of the disease. Rimmed vacuoles were present in one biopsy of an IBM patient, showing cN-1A expression around these rimmed vacuoles. Immunofluorescent cN-1A staining showed perinuclear cN-1A accumulation in all groups.

Interpretation: cN-1A is predominantly expressed in type 2 glycolytic myofibers and around myonuclei. These findings are not IBM-specific. The occasional expression of cN-1A in regenerating fibers in all groups encourages further research to clarify whether the presence of regenerating fibers is related to the development of anti-cN-1A autoreactivity.

## P121
### The German patient registry for inclusion body myositis

Sabine Krause, Simone Thiele, Marcel Heidemann, Karsten Schmidt, Matthias Vorgerd, Jens. Schmidt, Maggie C. Walter
Friedrich Baur Institute, Munic, Germany

**Correspondence:** Sabine Krause
BMC Rheumatology 2019, 3(Suppl 1):P121

**Objectives:** Inclusion body myositis (IBM) is a quite common form of myositis in patients aged over 50 years. It is a rare disease with an estimated prevalence between 4.5 and 9.5/million rising up to 50/ million for individuals over 50 years with clinical heterogeneity in different populations and ethnic groups. Patients suffer from slowly progressive muscle weakness resulting in severe disability and display varying degrees of dysphagia. No causative treatment is currently available but new therapeutic strategies are investigated and innovative clinical trials are expected in the coming years. A German patient registry for IBM was established to overcome the bottlenecks of data fragmentation, lack of harmonization and lack of trial readiness for this disease. We aim to include harmonized datasets of German patients diagnosed with IBM based on standardized clinical and histopathological findings (revised Hilton-Jones criteria)

**Methods:** A harmonized dataset including clinical data and muscle biopsy reports is recorded since 01/2016 using a dual patient and professional online report system (www.ibm-register.de). National legislation, data protection laws and ethical recommendations are strictly followed in this process. The registry aims at collecting high-quality, curated and regularly updated longitudinal data of the majority of German IBM patients. In addition, the registry may help to address research questions like prevalence, natural history and disease course.

**Results:** Currently, the registry is being used to evaluate up-to-date epidemiological data. In particular, the occurrence of swallowing disorder and the cN-1A autoantibody are being assessed.

**Conclusions:** The IBM registry provides the unique opportunity not only to characterize and effectively recruit German patients for international clinical trials and to support the translation of new therapies from "bench to bedside", but also to improve patient care by assessing standards of diagnosis and care.

## P122
### Inclusion Body Myositis (IBM) Symptom Flares and Associated Impact from the Patient Perspective

Antonis Kontekakis, Winnie Nelson¹, Lisa Christopher-Stine², William Kelly², Linda Kobert³, Barima Opong-Owusu¹, Michael Reed⁴

¹Mallinckrodt Pharmaceuticals; Mountain View, USA; ²Johns Hopkins University; Baltimore, USA; ³The Myositis Association; Alexandria, USA; ⁴Vedanta Research; Chapel Hill, USA

**Correspondence:** Antonis Kontekakis
BMC Rheumatology 2019, 3(Suppl 1):P122

**Objectives:** IBM is a progressive and chronic inflammatory myopathy in which flares, or worsening symptoms, have not been well characterized from the patient perspective. This analysis explores IBM symptom flare frequency, corresponding disability and rate of unplanned medical encounters from patient self-report.

**Methods:** Online surveys were collected from volunteer patients from The Myositis Association and Johns Hopkins Myositis Center. Socio-demographics, flare symptoms, Health Assessment Questionnaire Disability Index (HAQ-DI) and HAQ-Pain index, Patient Health Questionnaire (PHQ-4), emergency department and urgent care (ER/UC) visits and hospital admissions were assessed. Flare frequency was obtained by asking, "Have you ever had a flare or worsening myositis symptoms?" and if yes, "How many times in the past 12 months?"

**Results:** 233 individuals with a self-reported diagnosis of IBM completed the survey between December 2017 and May 2018. Recall of prior symptom flares was reported by 187 respondents (97.2% Caucasian, 31% female, 17.1% employed, mean age 68.9 years). Among the 187 respondents, 48 (25.7%) reported never having flares or no flares in the past year, 69 (36.9%) reported 1-3 flares, 35 (18.7%) reported 4-6 flares, and 35 (18.7%) reported 7 flares in the past year. Among the 139 respondents with self-reported flares in the past year, the most common worsened symptoms were muscle weakness (96%), trouble standing from a seated position (71%), trouble climbing stairs (67%), extreme fatigue (56%) and dysphagia (51%). Increasing flare frequency was associated with marginally significant HAQ-DI (F=2.177, P < .092) and significantly greater mean HAQ-Pain (F= 13.846, P < .001) as well as more PHQ anxiety (χ2=10.862, P < .012) and depression (χ2=7.061, P < .071). 15.5% reported past year ER/UC use, and 8.6% reported one or more hospital admissions, but neither was associated with flare frequency, perhaps due to the chronic and slowly progressive nature of IBM.

**Conclusion:** Despite being rarely described in the literature, self-reported symptom flares or periods of worsening symptoms were found to be common among patients with IBM, with 74% reporting one or more occurrences in the past year. Muscle weakness was the most common flare symptom, and dysphagia occurred in half of the patients during a flare. Flare frequency was associated with greater pain and more disability as well as greater risk of clinical anxiety and depression. Higher frequency of patient-reported flares may be a marker of worse physical and mental functioning and supports their importance in clinical assessment of IBM.

## P123
### Characterization of inflammation-induced mitochondrial cell stress in human skeletal muscle in vitro and ex vivo

Stefanie Meyer¹, Leila Scholle², Sabrina Zechel¹, Susann Kummer³, Jan Dudek⁴, Heiko Lorenz, Anna Hell¹, Christine Stadelmann¹, Stephan Zierz², Jana Zschüntzsch¹, Jens Schmidt¹

¹Universitätsmedizin Göttingen, Göttingen, Germany,

²Universitätsklinikum Halle, Halle, Germany; ³Universitätsklinikum Heidelberg, Heidelberg, Heidelberg, Germany; ⁴Universitätsklinikum Würzburg, Würzburg, Germany

**Correspondence:** Stefanie Meyer
BMC Rheumatology 2019, 3(Suppl 1):P123

**Objectives:** Inclusion body myositis (IBM) is a relatively common inflammatory myopathy (IM) in patients above fifty years of age. Typical finding in IBM muscle histopathology includes an autoreactive inflammation, degenerative changes and marked alterations of mitochondria. These include an abnormal mitochondrial proliferation, multiple deletions in the mitochondrial DNA and dysfunction of the cytochrome C oxidase (COX), a protein-complex of the mitochondrial respiratory chain. The role of these abundant mitochondrial alterations in IBM compared to other IM remains elusive. We hypothesized that inflammatory cell stress leads to mitochondrial dysfunction in human muscle cells and, thereby, causes muscle fiber damage and wasting.

**Methods:** Cell culture of primary myotubes from human non-myopathic muscle samples were exposed to pro-inflammatory cytokines such as interferon-gamma (IFN-γ) and interleukin-1beta (IL-1β). Relevant markers of fusion (Mfn1, Mfn2), fission (Drp1, Fis1), respiratory chain (COX IV) and transporter of the outer mitochondrial membrane (TOM20) were analyzed by qPCR, Immunocytochemistry and Western Blot. The enzyme activity of complexes of the respiratory chain was assessed using spectrophotometric analysis. Muscle biopsies of patients with IBM, polymyositis (PM), dermatomyositis (DM), necrotizing
myopathy (NM) and muscular dystrophies were studied for inflamma-
tory and mitochondrial changes by qPCR and Immunocytochemistry.

Results: After exposure to inflammatory cytokines, a significant increase of the Drp1 - and Fis1- expression in the cultured cells was noted as well as an increased fission of the mitochondrial network as evidenced by TOM20 staining. Additionally, a significant decrease of the COXIV - protein amount upon pro-inflammatory cytokines was noted. IBM muscle biopsies displayed a significant increase of COX - deficient fibers, ragged red fibers and rimmed vacuoles, which confirmed IBM by means of histopathology. In all IBM biopsies, an increased expression of Fis1 and Drp1 was detected in comparison to non- myopathic muscle.

Conclusion: Using an established cell culture model for myositis, the results demonstrate that pro-inflammatory cytokines lead to a shift of mitochondrial dynamics towards fission and decreased expression of respiratory chain proteins. Ex vivo data of IM patients is in line with the in vitro findings, showing signs of increased fission processsing. The data offer an explanation how myoinflammation can lead to muscle fiber damage through alterations of mitochondrial dynamics and consecutive dysfunction. These findings could be relevant for developing new therapeutic strategies e.g. mitochondrial protective molecules, to reduce the burden of chronic muscle inflammation.

P124

Fingolimod and IgG in experimental treatment of an IBM mouse model for muscle regeneration

Per-Ole Carstens, Sebastian Höller, Alexis Grimm, Jens Schmidt

Universitätsmedizin Göttingen, Göttingen, Germany

**Correspondence:** Per-Ole Carstens

BMC Rheumatology 2019, 3(Suppl 1):P124

Objectives: Inclusion body myositis (IBM) is an autoimmune-mediated inflammatory myopathy, which is resistant to immunosuppressive treatment. The complex pathophysiology is characterized by mechanisms of inflammation, degeneration and an impaired regenerative capacity. Our aims were i) to establish a model of muscle regeneration in IBM mice and ii) to analyze the effects of fingolimod and immunoglobulins (IgG) on regeneration.

Methods: As an animal model, double transgenic mice with a muscle specific overexpression of amyloid precursor protein (APP, Swedish mutation) and a mutated presenilin, leading to an IBM-like phenotype were used (hereinafter referred to as "IBM mice"). Muscle damage was induced by the injection of the venom notexin into the right tibialis anterior muscle. The left muscle was treated with saline as a solvent control. 14 animals were treated with fingolimod, which was administered daily via the drinking water (dose: 3 mg/kg). 16 animals were treated with IgG injected intraperitoneally at day 0 and 1 (dose: 1 g/kg). 30 animals remained untreated. For clinical assessment, mice were scored daily by a score adapted from the experimental autoimmune myositis scale, which ranges from 5 (paralysis of the complete hind leg) to 0 (normal). Additionally, the grip strength was measured daily. At day 10, all animals were sacrificed and the tibialis muscle of both sides were analyzed. The muscle regeneration and necrosis were analyzed by histology and the levels of mRNA expression for markers of regeneration (myogenin, MyoD, PAX7), inflammation (IL-1β, CXCL-9) and atrophy (Trim63) were measured by qRT-PCR.

Results: The clinical scoring and grip strength displayed no differences between treated and untreated animals. Both groups had an initial mean score of 4 after the notexin injection and improved to a score around 1 at day 10. Histologically, the degree of regeneration and necrosis was comparable in both treatment groups compared to controls and analysis by qRT-PCR did not produce relevant differences.

Conclusions: Impaired muscle regeneration is a relevant part of the complex pathophysiology of IBM. We were able to establish a model of muscle regeneration in the IBM mouse, but our treatment attempts failed. Reasons could be, that the treatment start is at the same time point as the muscle damage, which might be to late. Another explanation could be, that IgG and fingolimod are generally not operative in regenerative pathways in the skeletal muscle. More

studies are needed to further elucidate novel pharmacological ap-
proaches in experimental regeneration in mouse muscle.

P125

Clinical mimics of inclusion body myositis and how to recognize them

Stefanie Glaubitz, Rachel Zeng, Karsten Schmidt, Per-Ole Carstens, Mateja

Smogavec, Jens Schmidt, Jana Zschüntzsch

Universitätsklinikum Göttingen, Göttingen, Gemany

**Correspondence:** Stefanie Glaubitz

BMC Rheumatology 2019, 3(Suppl 1):P125

Background: Inclusion body myositis (IBM) is an idiopathic inflammatory myopathy with typical clinical symptoms and histological features. However, due to a range of acquired or genetically determined myopathies with similar presentations, IBM is often missed and diagnosed in error as another neuromuscular disease.

Objective: To discuss and identify clinical pitfalls in the diagnosis of IBM by means of case reports.

Methods: We provide typical case reports of facioscapulohumeral muscular dystrophy (FSHD), titinopathy (TMD/LGMD2J), anoctaminopathy (LGMD2L), polymyositis and other neuromuscular diseases that can mimic IBM. The data are carefully discussed and typical clinical pitfalls are summarized.

Results: Along with dermatomyositis, polymyositis, overlap myositis and (immune mediated) necrotizing myopathy, IBM belongs to the group of idiopathic inflammatory myopathies (IIM). The typical clinical presentation of IBM involves slowly progressive muscle atrophy and weakness with a preference of long finger flexors, knee and foot extensors, often with an asymmetric distribution. Other symptoms may include myalgia and dysphagia. The diagnosis of IBM is currently based on a defined composition of clinical, serological and muscle histologic criteria. Additionally, electromyography, muscle MRI and muscle ultrasound may help to confirm the diagnosis. A muscle biopsy is required to diagnose a clinico-pathologically defined IBM, showing the co-existence of myodegenerative and inflammatory pathologic features. Nevertheless, the diagnosis of IBM or especially the differentiation from other neuromuscular diseases can be difficult due to atypical clinical presentations. Histopathological findings can also lead to confusion since inflammatory infiltrates can also be found in hereditary myopathies like dysferlinopathy or facioscapulohumeral dystrophy. The myodegenerative characteristics of myofibrillar myopathies like vacuoles and abnormal accumulations of filamentous proteins can also be mistaken.

Conclusion: IBM is often missed and diagnosed in error as another neuromuscular disease. However, careful consideration of clinical and histopathological features can help to differentiate IBM from other neuromuscular diseases and lead to the correct diagnosis. Only a correct and reliable diagnosis of IBM allows for recruitment to clinical studies and helps to find novel, exploratory treatment modalities and prevent unnecessary treatments.

P126

Clinical profile of inclusion body myositis/myopathy (IBM) in a
referral neuromuscular center

Payam Soltanzadeh¹, Nimish Thakore², Richard Prayson², Kerry Levin²

¹UCLA, Los Angeles, USA; ²Cleveland Clinic, Ohio, USA

**Correspondence:** Payam Soltanzadeh

BMC Rheumatology 2019, 3(Suppl 1):P126

Objectives: Clinical overview of a large series of inclusion body myositis/myopathy (IBM) patients from a referral neuromuscular center.

Methods: We identified patients with the diagnosis of inclusion body myositis/myopathy (IBM) who were referred to the Cleveland Clinic Neuromuscular Center in Cleveland Ohio (USA) between February 2012 and October 2017. Griggs, ENMC, and MRC criteria were used to stratify patients into different diagnostic categories based on clinical, electrodiagnostic, and pathologic findings. Creatine kinase (CK) levels, age of onset, initial symptoms or presenting features, major
electromyographic (EMG) findings, and relevant laboratory data were also collected.

Results: One hundred and seven (107) patients were identified among whom 95 were still alive at the time of study enrollment. Fifty-one patients had detailed biopsy findings consistent with the diagnosis of sporadic IBM (sIBM), among whom one had HIV infection and one had chronic hepatitis C disease. Among the 49 pathologically "pure" sIBM, 21 had "definite" sIBM per Griggs criteria, 38 had "definite" sIBM per ENMC criteria, and 26 had "clinically defined" sIBM per MRC criteria. In patients with ENMC definite sIBM, 23 (60%) presented with proximal leg weakness and two patients with asymptomatic hyperCKemia. Irritable myopathy with mixed neurogenic and myopathic motor units was the most common electrodiagnostic pattern in patients with sIBM. Irritable myopathy in forearm flexor muscles was commonly noted in patients with sIBM. Fragile X-associated tremor and ataxia syndrome (FXTAS), VCP proteinopathy, and GNE myopathy were the genetic muscle diseases mimicking sIBM.

Conclusion: Diagnostic certainty of sporadic inclusion body myositis (sIBM) varies depending on what criteria are used. More patients are now diagnosed with sIBM based on clinical and EMG criteria without getting muscle biopsies. Infectious and genetic muscle diseases can mimic sIBM and asymptomatic hyperCKemia could also be a presenting feature.

## P127

### Characterising the immune response associated with Inclusion Body Myositis

Jerome Coudert¹, Kelly Beer¹, Phillipa Lamont², Merrilee Needham¹

¹Murdoch University, Murdoch, Australia; ²Royal Perth Hospital, Perth, Australia

Correspondence: Jerome Coudert

BMC Rheumatology 2019, **3**(Suppl 1):P127

Background: Inclusion body myositis (IBM) is the most common acquired skeletal muscle disease associated with aging and occurs more commonly in men. It is relentlessly progressive over time resulting in muscle wasting and loss of function, which negatively impacts patient mobility and quality of life. Histologically, IBM is characterised by a combination of inflammatory and degenerative changes. Immune cells accumulate within the endomysium, and surround and invade the myofibres. They are mainly composed of T-cells and macrophages. In addition, myofibers express upregulated MHC class I molecules on their surface thereby behaving as antigen presenting cells, promoting antigen presentation to and targeting by cytotoxic CD8+ T cells. The biological mechanisms responsible for IBM aetiology appear to be quite unique, and as a result, conventional immunosuppressive treatments which are used in other inflammatory myopathies are not effective and often even have deleterious effects. Objectives: A detailed characterisation of the autoimmune response in IBM over time is therefore necessary to understand the cellular and molecular basis of this dysregulation and to design more targeted therapies.

Methods: We undertook to analyse the immune system in the blood of our patients using a flow cytometry-based approach, in order to identify changes occurring over time. In addition, we analysed the T-cell receptor (TCR) variability; these molecules are generated upon rearrangement of the genes that encodes the TCR region. Each T-cell possesses a unique gene rearrangement and accumulation of cells expressing identical TCR demonstrates clonal expansion in response to a particular antigen. The CDR3 is a highly variable domain of the TCR and it constitutes the molecular basis for T-cell specificity. We sequenced the TCR of T-cell subsets isolated from the blood and from diseased muscles to identify potential predominant TCR gene rearrangements and CDR3.

Results: The flow cytometry analysis revealed high frequencies of circulating activated / memory T lymphocyte subsets with evidence of inflammatory and cytotoxic functions. The presence of inflammatory macrophages was also evident. The analysis of TCR variability using next generation sequencing revealed clonally expanded T cells both within muscles and in the blood.

Conclusion: We expect that our work using newly available technologies will provide critical information building on previous studies, to understand what drives the autoimmune response associated with IBM and will help identifying the antigen responsible for the auto-reactive T cells, overall paving the way toward more targeted and successful therapies.

## P128

### Association of HLA with anti-cN1A antibodies in IBM patients

Jerome Coudert¹, Kelly Beer¹, Christine Bundell², Anna Brusch², Abha Chopra¹, Merrilee Needham¹

¹Murdoch University, Murdoch, Australia; ²PathWest, Nedlands, Australia

Correspondence: Jerome Coudert

BMC Rheumatology 2019, **3**(Suppl 1):P128

Background: Inclusion body myositis (IBM) is the most common acquired skeletal muscle disease associated with aging. It is relentlessly progressive over time resulting in muscle wasting and loss of function, which has a major impact on their quality of life and ability to live independently. Histologically, IBM is characterised by a combination of inflammatory and degenerative changes. Immune cells accumulate within muscle tissues, surround and invade the myofibres; they are mainly composed of T-cells as well as macrophages. The local production of inflammatory cytokines and chemokines further recruits and stimulate leucocytes, while exacerbating the degenerative process in myofibres manifesting as protein accumulation. Recent findings revealed the presence of autoantibodies in many patients, suggesting that B-cells may also play a role in IBM pathogenesis. We found in one third of our IBM patients antibodies against cytosolic 5'-nucleotidase 1A (cN1A). cN1A is a cytosolic enzyme involved in the conversion of adenosine monophosphate (AMP) to adenosine and catalyses the hydrolysis of nucleotides to nucleosides. cN1A is most abundant in skeletal muscles. In IBM, it is aberrantly distributed within muscle in areas of myofibres degeneration. However anti-cN1A is rarely detected in other forms of inflammatory myopathies, suggesting it could have potential as a biomarker in this clinical context of myositis. Even though the precise role of anti-cN1A remains uncertain in IBM, results obtained from experimental animal models suggests that these antibodies may have a pathogenic role in myofibre degeneration.

Objectives: We hypothesised that the production of anti-cN1A in IBM patients was associated with genetic factors such as HLA allotype.

Methods: We analysed samples from IBM patients that are both positive and negative for the anti-cN1A antibodies. Serum samples were analysed by ELISA for the presence of anti-cN1A antibodies while DNA isolated from blood cells was sequenced by Illumina next generation sequencing to define the HLA haplotype of these patient groups.

Conclusion: Knowledge of association of HLA carriage with anti-cN1A production may further improve the diagnostic power and specificity of anti-cN1A antibody testing for IBM, whilst requiring only a slightly larger blood sample rather than requiring a far much invasive muscle biopsy. If future studies confirm that these antibodies are not only biomarkers but also mediate muscle damages, HLA typing will provide a predictive test before circulating anti-cN1A reach conclusive levels; which may support the implementation of antibody-specific treatments.

## P129

### Reliability and validity of an activity limitation measure in persons with IBM

Malin Regardt¹, Lisa Christopher Stine²

¹Karolinska University Hospital, Stockholm, Sweden; ²John Hopkins University, Baltimore, USA

Correspondence: Malin Regardt

BMC Rheumatology 2019, **3**(Suppl 1):P129

Objective: The aim of this study was to test validity and reliability of the questionnaire Disability in the Arm Shoulder and Hand (DASH) for patients with IBM. A second aim was to describe activity
limitation measured by the Canadian occupational Performance measure (COPM).

**Method:** Persons diagnosed with IBM were identified through the Swedish Myositis Network (SweMyoNet) quality registry in Stockholm Sweden. A total of 36 persons with IBM were included in the registry and were invited to participate. A total of 17 men and 9 women agreed to participate. Median (Q1-Q3) age was 74 (70-79) years and the median (Q1-Q3) disease duration was 7 (3-8) years. Activity limitation were assessed by the questionnaire Disability of the Arm, Shoulder and Hand (DASH) and the The Canadian occupational performance measure (COPM) which investigate patient derived areas of daily activities. The data collection was performed at the Karolinska university hospital in Stockholm Sweden. At baseline both DASH and COPM were performed. The participants received a second DASH questionnaire to be answered within two weeks (Follow-up) and send back to the researcher.

**Results:** There were good correlations between baseline measure and follow-up on DASH (rs 0.997; p=0.01) Indicating that the DASH is consistent over a short period of time. The results from COPM showed a variety of activities persons with IBM experienced problem with. Area with most activity limitations were basic self-care area such as dressing and grooming, fall, feeding, managing communication. Instrumental activities such as managing instruments, shopping and meal preparation. Leisure activities such as playing an instrument, run, paint and social activities such as visit friends, social engagements. Some of these activities were found in the DASH but not all. E.g. missing socializing with friends and family, problems swallowing or were environment dependent

**Conclusion:** The results indicate that DASH have a good test re-test reliability DASH includes some of the activities that persons with IBM experience difficulties with but not all. The participants experienced difficulties in all areas of life.

## P130

### B cell mechanisms in chronic muscle inflammation

Per-Ole Carstens¹, Luisa Müllar¹, Arne Wrede², Martin Wachowski¹, Almuth Brandis³, Sabine Krause⁴, Stephan Zierz⁵, Jens Schmidt¹

¹University Medical Center Göttingen, Göttingen, Germany; ²Saarland University Medical Center, Saarland, Germany; ³Klinikum Region Hannover, Hannover, Germany; ⁴Ludwig-Maximilians-University of München, Munic, Germany; ⁵University Hospital Halle/Saale, Halle, Germany

**Correspondence:** Per-Ole Carstens

BMC Rheumatology 2019, **3**(Suppl 1):P130

**Objectives:** Inclusion body myositis (IBM) and polymyositis (PM) are autoimmune-mediated myopathies, typically with a chronic disease course and development of paresis and impaired ambulation. The pathophysiology is complex and characterized by mechanisms of inflammation with predominance of T cells and macrophages. Beside these mechanisms, several autoantibodies have been identified in myositis and point towards a relevant involvement of B-cell-immunity. Our aim was to identify B-cell-mediated immunomechanisms in myositis. We studied the B cell activating factors BAFF and APRIL and the chemokines that control recruitment of B cells in vitro and ex vivo in IBM and PM compared to muscular dystrophies and non-myopathic controls.

**Methods:** Muscle biopsy specimen from patients with IBM (n=9), PM (n=9), muscular dystrophy (n=9) and non-myopathic controls (n=9) were analyzed for mRNA-expression of BAFF, APRIL, CXCL-12 and CXCL-13 and serial sections of skeletal muscle biopsies were stained for BAFF and CXCL-12. Myotubes derived from patients without myopathic changes were exposed to an inflammatory environment and the mRNA expression as well as the protein expression of BAFF, APRIL, CXCL-12 and CXCL-13 were measured by qPCR and by immunocytochemistry.

**Results:** The mRNA-expression of BAFF, APRIL and CXCL-13 was significantly higher in IBM and PM compared to healthy controls. In IBM, also the mRNA-expression of CXCL-12 was significantly higher. Muscles of patients with IBM displayed the largest proportion of positive stained muscle fibers for BAFF and CXCL-12. The exposure of myotubes to IFN-γ or IL-1β, respectively, led to a significant mRNA upregulation of BAFF and CXCL-12. The expression of APRIL and CXCL-13 was not altered by these cytokines. Immunocytochemistry showed a trend for upregulated protein-levels of BAFF and CXCL-12 in human myotubes.

**Conclusions:** Our results substantiate the hypothesis of an involvement of B cell-associated mechanisms in the pathophysiology of IBM and PM. The muscle fibers themselves may participate in the survival and differentiation of B cells and maintain the inflammation.

## P131

### Active immunization mice model of sporadic inclusion body myositis

Nozomu Tawara

Graduate School of Medical Sciences Kumamoto University, Kumamoto, Japan

BMC Rheumatology 2019, **3**(Suppl 1):P131

**Objective:** Sporadic inclusion body myositis (sIBM) is the most frequent acquired inflammatory myopathy in patients older than 50 years of age. Lack of effective treatments and unclearness of pathogenesis in sIBM may be associated with absence of appropriate animal models. Recently, an autoantibody against cytoplasmic 5'-nucleotidase 1a (cN1A) was identified in the sera of patients with sIBM. In the current study, we aimed to generate the active immunization mice model using with cN1A peptides to realize the pathogenesis of sIBM.

**Methods:** Three different sequences of cN1A peptides (P1, P2, and P3) with complete Freund's adjuvant (CFA) were injected into the bilateral foot pads of C57BL/6J mice (n= 5 per each peptide). Pertusis toxins (PT) were injected intraperitoneally at the same time. Injection of peptides and CFA were repeated 3 times every week. As control mice, CFA and PT were injected alone. We evaluated time course of body weight, motor activity, myopathological changes and protein expression levels of autophagy relating proteins.

**Results:** The mice injected with cN1A peptide showed significant differences in motor activity. Myopathological analysis revealed inflammatory cellular infiltrates in the peptide injected mice. Western blotting analysis showed that p62 was upregulated in peptide injected mice.

**Conclusions:** The mice immunized with specific cN1A peptide can mimic partly clinicopathological phenotypes of sIBM. cN1A active immunization mice can be an appropriate animal model to elucidate pathogenesis and to search effective treatment of sIBM.

## P132

### Unravelling the pathogenesis of brachio-cervical myopathy associated to Scleroderma

Xavier Suárez-Calvet, Eduard Gallardo, Jorge Alonso-Pérez, Ivan Castellví, Ana Carrasco-Rozas, Alicia Alonso-Jimenez, Susana López-Fernández, Joana Turón-Sans, Ricard Rojas-Garcia, Jordi Díaz-Manera
¹Sant Pau Biomedical Research Institute, Barcelona, Spain

**Correspondence:** Xavier Suárez-Calvet

BMC Rheumatology 2019, **3**(Suppl 1):P132

**Objectives:** To describe patients with brachio-cervical myopathy associated to Scleroderma from a clinical, serological and histological point of view. To elucidate specific pathogenic events occurring in these patients using in vitro experiments.

**Methods:** We reviewed clinical, immunologic, muscle MRI, capillaroscopy, muscle biopsy and response to treatment data from the patients. Cytokine arrays were performed using sera from age and sex-matched controls, scleroderma patients and from our cohort. In vitro, we analyzed the effect of dysregulated molecules on human cells that are presumably involved in the pathogenesis of this disease such as muscle cells, fibroblasts, endothelial cells and fibroadipogenic progenitors.

**Results:** Herein we describe 11 patients with brachio-cervical inflammatory myopathy, 10 women and one man. Symptoms at onset were
neck and proximal upper limbs muscle weakness with relative sparing of lower limbs. Mean age of symptoms onset was 51.2 years old. All patients had associated features of scleroderma, like thickening of the skin, sclerodactylia, facial telangiectasias or Raynaud's phenomenon. Dysphagia was present in 72.2% of patients and lung involvement in 36.6% of patients. Capillaroscopy showed a scleroderma pattern in six patients. Antibody tests were negative except for some patients who presented different reactivities (one ACA-B, one SSA/Ro, two Th/To and one anti-Ku and anti-Mi2). Muscle biopsies showed fiber size variability, necrosis, fibrosis and increased expression of MHC class I. A variable degree of macrophage infiltration was observed, and some biopsies showed CD20, CD4 and CD8 infiltrates and complement deposition. Cytokine arrays showed dysregulated cytokines involved in fibrosis, inflammation and angiogenesis. We are investigating in vitro whether the dysregulated molecules present in the sera of patients reproduce our in vivo observations. Ongoing studies of proliferation, migration, differentiation and gene expression will elucidate the specific role of these molecules in the pathogenesis of this particular form of myositis.

Conclusion: We present a significant number of patients with a poorly reported association between brachio-cervical myopathy and scleroderma which is manifested as a form of myositis. It is imperative to consider this entity because a correct diagnosis has important implications for treatment. Expanding the knowledge of this entity will help to understand the specific mechanisms implicated in the muscle degeneration observed.

## P133

### Vacuolar myopathy with monoclonal gammapathy and stiffness: A new Monoclonal gammopathy of muscle significance

Yves Allenbach¹, Emmanuelle Salort-Campana², Edoardo Malfatti³, Bruno Eymard⁴, Shahram Attarian², Andre Maues de Paula², Aude Rigolet⁴, Sarah Leonard-Louis⁴, Olivier Benveniste⁴, Tanya Stojkovic⁴

¹Sorbonne Universités, Paris, France; ²Assistance Publique-Hôpitaux Marseille, Marseille, France; ³Assistance publique-Hôpitaux de Paris, Paris, France; ⁴Hôpital Pitié-Salpetrière, Paris, France

**Correspondence:** Yves Allenbach

BMC Rheumatology 2019, 3(Suppl 1):P133

**Objective:** Monoclonal gammopathy have been related with numerous neurological disorders but the spectrum of associated myopathies remains poorly described. We report a new acquired myopathy associated with monoclonal gammopathy.

**Methods:** Three patients were prospectively analysed. In addition to patients' characteristics, electrophysiological data, muscle biopsy analysis and outcomes of patients were collected.

**Results:** Three patients aged from 38 to 56 years were analysed. All suffered from a muscle weakness with a sub-acute onset and stiffness, in a context of severe weight loss. The muscle deficit mainly involved the proximal limbs and axial muscles. Creatine kinase level was increased [1400-2900 IU/L] and electromyography revealed a myogenic pattern and spontaneous high frequency discharges. Muscle biopsies showed the association of vacuoles filled with glycogen and mild inflammation. There was no evidence for genetic glycogen metabolic disorder. IgGk monoclonal gammopathy was identified in all cases. There was no sign of lymphoplasmocytic proliferation. All patients improved with a treatment combining corticosteroid, intravenous immunoglobulin and immunosuppressants, and dramatic improvement was observed in two patients.

**Conclusion:** we reported a new monoclonal gammopathy associated muscle disease defined by a vacuolar myopathy characterized by axial and proximal muscle weakness with prominent stiffness and high frequency discharges on electromyography.

## P134

### Characteristics of myositis - rheumatoid arthritis overlap patients in a Hungarian cohort

Levente Bodoki¹, Zoltán Griger¹, Melinda Nagy-Vincze¹, Zoe Betteridge², Katalin Dankó¹

¹University of Debrecen, Debrecen, Hungary; ²Bath Institute for Rheumatic Diseases, Bath, UK

**Correspondence:** Levente Bodoki

BMC Rheumatology 2019, 3(Suppl 1):P134

Overlap syndromes are autoimmune disorders in which classification criteria of at least two connective tissue diseases (CTDs) are fulfilled. The Division of Clinical Immunology in Debrecen, Hungary oversees patients with idiopathic inflammatory myopathies (IIMs) since the 1980's. In a work called The Myositis Antibody Research Project, which is coordinated together with the Bath Institute for Rheumatic Diseases (UK), authors investigated 330 patients with myositis, all treated in this Hungarian center. The aim of this retrospective study was to investigate the frequency, clinical and serological parameters and therapeutic options in myositis - rheumatoid arthritis overlap cases in this group of 330 patients. The frequency of overlap cases, as seen in literature, was 13.64%. The importance of myositis-associated antibodies (MAAs) can be seen on this results: 44.44% of overlap patients, while only 7.02% of not overlap patients were MAA positive. Out of our 45 overlap patients twenty-seven myositis - RA overlap patients could be identified. Among these 27 patients the women:men ratio was 12.5:1, PM:DM ratio was 2.375:1. Muscle weakness and skeletal involvement was present in every patient, myalgia in 77.78% and Raynaud's phenomenon in 48.15% of the patients; general symptoms during disease relapse (fatigue, weight loss, fever) were present in 59.26%, 18.52% and 14.82%, respectively. Ten cases had seropositive rheumatoid arthritis, with high titer of rheumatoid factor. Authors underline the importance of lung involvement as internal organ manifestation: 8 patients had anti-synthetase antibodies (six anti-Jo-1, one anti-PL-7 and one anti-PL-12). In anti-PL-7 and anti-PL-12 positive patients interstitial lung disease (ILD) appeared some years before myositis and early aggressive management of ILD resulted in fast remission of muscle weakness. Anti-Mi2 and anti-SRP could be detected in two patients. Most frequent used disease modifying antirheumatic drugs were cyclophosphamide, methotrexate and cyclosporine, 19 patients received DMARD combination therapy. Biological therapy was used in 3 patients, intravenous or subcutaneous immunoglobulin in 4 patients and one patient with RA - myositis - antiphospholipid syndrome died because of asipartion pneumonia. Authors conclude that it is really challenging to treat these overlap cases: they form a very heterogenous group of patients and management has to be personalized.

## P135

### The Role of Muscle Biopsy Score in the Prediction of the Outcome of Adult Idiopathic Inflammatory Myopathies

Xin Lu, Xiaoxiao Zheng, Lining Zhang, Xiaolan Tian, Qingyan Liu, Wenli

Li, Qinglin Peng, Guochun Wang

China Japan Friendship Hospital, Beijing, China

**Correspondence:** Xin Lu

BMC Rheumatology 2019, 3(Suppl 1):P135

**Objective:** The aim of the study was to investigate the relationship between the quantitative muscle biopsy score (qMBS) and prognosis of adult patients with idiopathic inflammatory myopathies (IIM).

**Methods:** Muscle biopsy was taken from biceps brachii muscle in 326 dermatomyositis and 89 polymyositis patients according to 1975 Bohan&P-eter criteria. Muscle frozen sections were performed immunohistochemical