AB0607 MYOSITIS-RELATED INTERSTITIAL LUNG DISEASES: CLINICAL FEATURES, BIOMARKERS AND AUTOANTIBODIES IN LATINOAMERICAN PATIENTS
Authors: S. M. Sánchez Romo, G. G. Sánchez Mendieta, M. A. Villarreal-Alarcón, I. D. J. Hernandez-Galarza, D. Á. Galarza-Delgado
Journal: Annals of the Rheumatic Diseases (2020)

Background: The lung is one of the most common extra-muscular targets in idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) is a prevalent and often devastating manifestation of IIM 1 . Objectives: To know the frequency of autoantibodies associated with IMM-ILD, biomarkers, and their relation with clinical features in patients with IIM. Methods: Adults with IIM were enrolled in a retrospective way. Demographics, clinical and laboratory features were registered. The determination of antibodies was perfomed by the Inmunoblot technique with Euroinmmun kit. Patients without a myositis antibody panel were excluded. The diagnosis of ILD was based on HRCT. Patients with anti-MDA5 antibodies and with anti Ro-52 antibodies associated with anti-ARS were considered as high risk group, those with anti-ARS, anti-U1-RNP, anti-PM/ Scl and anti-Ku antibodies as moderate risk and those with anti-Mi2, anti SRP and anti TIF1 antibodies as low risk 2 . Results: Demographics characteristics are shown in table 1. We included 36 patients. Dermatomyositis (DM) was described in 69.4%, polymyositis (PM) in 16.7% and antysnthetase syndrome (AAS) in 13.9%. Out of the total of our patients, 30.6% had interstitial lung disease. The most frequent autoantibody was Anti Ro52 in 13 (36.1%) patients and 44.4% were in the high risk group. We analized our patients by the presence or absence of ILD and we found that anti-MDA5 antibodies were more frequent in IMM-ILD group (p=0.006). In our IMM-ILD group we compared the autoantibodies with the clinical and serological features and we found that patients with IMM- ILD and anti Ro-52 antibody had more frequency of heliotrope rash (p=0.045) and those with IMM- ILD and anti-Jo1 antibody had a higher level of CK (p&lt;0.001). Table 1. Demographic characteristics Age, mean SD 40.611 +/- 16.37 Women, n(% ) 24 (66.7%) Diagnosis Dermatomiositis 25 (69.4%) Polimiositis 6 (16.7%) Síndrome antisintetasa 5 (13.9%) Time of evolution * 6.00 (2.25 – 19.00) Interstitial lung disease 11 (30.6%) Serological CK 305.00 (50.75 – 1969.250) LDH 460.727 +/- 384.76 Risk ILD complicated with IIM High 16 (44.4%) Moderate 8 (22.2%) Low 12 (33.3%) *months Table 2. Clinical and serological comparation between IMM groups with and without ILD IMM with ILD, n=11 IMM without ILD, n=25 p Proximal muscle weakness 10 (90.9%) 22 (88.0%) NS Heliotrope Rash 7 (63.6%) 10 (40.0%) NS Mechanic hands 4 (36.4%) 4 (16.0%) NS Anti-Mi-2 2 (18.2%) 8 (32.0%) NS Anti-Tif1 γ 0 (0.0%) 6 (24.0%) NS Anti-MDA5 4 (36.4%) 0 (0.0%) .006 Anti-NXP2 1 (9.1%) 0 (0.0%) NS Anti-SAE1 0 (0.0%) 1 (4.0%) NS Anti-Ku 0 (0.0%) 2 (8.0%) NS Anti-PM/Scl100 0 (0.0%) 1 (4.0%) NS Anti-PM/Scl75 2 (18.2%) 0 (0.0%) NS Anti-Jo1 1 (9.1%) 0 (0.0%) NS Anti-SRP 0 (0.0%) 3 (12.0%) NS Anti- PL12 0 (0%) 1 (4.0%) NS Anti-EJ 1 (0.1%) 1 (4.0%) NS Anti- PL7 1 (9.1%) 4 (16.0%) NS Anti-OJ 0 (0.0%) 2 (8.0%) NS Anti-Ro52 5 (45.5%) 8 (32.0%) NS Conclusion: Anti-MDA5 antibodies were more frequent in our IMM-ILD group than in IMM without ILD group. Almost half of our patients were in a high risk group, which means they need an early immunosuppressive treatment. In our IMM-ILD patients we found an association between the presence of anti Ro-52 antibody with heliotrope rash and of anti-Jo1 antibody to a higher level of CK. References: [1]Saketkoo, L. A., et al. (2010). Interstitial lung disease in idiopathic inflammatory myopathy. Current Rheumatology Reviews, 6(2), 108-119. [2]H. Yoshifuji, “Biomarkers and Autoantibodies of Interstitial Lung Disease with Idiopathic Inflammatory Myopathies,” Clin. Med. Insights Circ. Respir. Pulm. Med., vol. 9s1, pp. 141–147, 2015. Disclosure of Interests: None declared