FRI0589 IS THERE AN OVERLAP OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODY-ASSOCIATED VASCULITIDES WITH IGG4-RELATED DISEASE OR NOT?
Authors: Abdulsamet Erden, Ertuğrul Çağrı Bölek, Gözde Kübra Yardımcı, Şule Apraş Bilgen, Omer Karadag
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Pseudotumor orbita, pachymeningitis, periaortitis could be seen in both ANCA-associated vasculitis and IgG4-RD. Sometimes it may be difficult to differentiate these two entities. The co-occurrence/concurrence of Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) and IgG4-related disease (IgG4-RD) was recently published by a collaborative EUVAS group [1]. <h3>Objectives</h3> Firstly, we aimed to investigate ANCA positivity of our IGG4-RD cohort. Secondly, a literature review of co-occurrence/concurrence of AAV and IgG4-RD was done. <h3>Methods</h3> Data of totally 62 patients with IgG4-RD in Hacettepe Vasculitis Center Database was used. Patients were diagnosed with IgG4-RD according to comprehensive diagnostic criteria [2]. Dataset of patients including demographic data, clinical characteristics, and imaging and laboratory findings of IgG4-RD was re-evaluated in terms of AAV and ANCA test. At next step, we performed a systematic literature review of the PUBMED database covering the time period until April 2018. Relevant publications were searched using the MeSH terms “IgG4-related disease and Eosinophilic Granulomatosis with Polyangiitis”, ‘‘IgG4-related disease and Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis” and “IgG4-related disease and Granulomatosis with Polyangiitis”. <h3>Results</h3> Totally 29 (46.7%) of our patients had ANCA results. Out of 29 patients 15 (51.7%) were considered as probable, 10 (34.5%) as definite and 4 as possible (13.8%) for IgG4-RD. Three (10.3%) of these patients had ANCA positivity. All of these ANCA titers were in low degree positivity (MPO-ANCA 1/100, MPO-ANCA 1/32 and PR3 ANCA 1/100). These three patients didn’t have any findings of vasculitis and didn’t have granuloma in their biopsy. When we evaluate these three patients with regards to meeting the Ig G4- RD criteria, 1 was definite, 1 was probable and 1 was possible. In literature review, we found 17 cases that having both features of IgG4-RD and AAV (Table). These cases were re-evaluated according to the ‘Comprehensive Diagnostic Criteria for IgG4-RD’. Diagnoses of IgG4-RD were definite in 11 cases (64.7%), probable in 2 cases (11.8%) and possible in 4 cases (23.5%). ANCA were positive in 15 of 17 patients (88%). ANCA were directed against proteinase 3 (PR3-ANCA) in 6 patients and were directed against myeloperoxidase (MPO-ANCA) in 5 patients. Other four cases had both MPO-ANCA and PR3-ANCA. All PR3-ANCA positive cases have high titers of ANCA, whereas only one MPO-ANCA positive case has high titers of ANCA. <h3>Conclusion</h3> None of our IgG4-RD patients have any overlap with ANCA-associated vasculitis. Only in 3 patients (10.3%), ANCA positivity was detected without any histopathologic evidence. Just two patients of literature review, seemed to be full compatible with both diseases. Even though ANCA-associated vasculitis and IgG4-RD share clinical features, we think this might be as co-occurrence instead of a histopathologic link. <h3>References</h3> [1] Danlos, FX. Autoimmun Rev, 2017. [2] Umehara, H. Mod Rheumatol, 2012. <h3>Disclosure of Interests</h3> None declared