AB0680 Autoantibodies in Idiopathic Inflammatory Myopathies

• Published in: Annals of the rheumatic diseases Vol. 74; no. Suppl 2; p. 1125
• Main Authors: Faten, A., Laadhar, L., Ben Ghorbel, I., Kallel-Sellami, M., Houman, H.
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group LTD 01.06.2015
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2015-eular.2845

BackgroundIdiopathic inflammatory myopathies (IIM) are autoimmune diseases characterized by inflammation of skeletal muscle tissue. There are several clinical entities: polymyositis (PM), dermatomyositis (DM), the inclusions body myositis (MI), the anti-synthetase syndrome (ASS), etc.ObjectivesThe objective of this study was to determine the prevalence of a wide range of autoantibodies in patients with IIM.MethodsWe identified all patients with IIM addressed by the Internal Medicine Department, between January 2006 and February 2014 for immunological tests.The myositic-specific antibodies MSA (anti-Mi-2, anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, anti-SRP) and the myositic-associated antibodies MAA (anti-Ku, ani-PM-Scl75, anti-PM-Scl100, anti-Ro-52) were detected by immunodot (Euroimmun®).Other antibodies were also investigated: anti-nuclear antibodies (ANA) by indirect immunofluorescence on Hep2 cells (Biorad®), anti-soluble nuclear antigens antibodies (anti-ENA), anti-DNA antibodies, anti-thyroperoxydases (ATPO), anti-thyroglobulins (Athy) and rheumatoid factors (RF) by Elisa (Human®).ResultsWe identified 54 patients including 10 with PM, 36 with DM and 8 with ASS. It was 41 women and 13 men with an average age of 44 years [range: 12-74 years]. More than half (28/54) had an associated autoimmune disease.MSA were detected in 38 patients (70%). Among these antibodies, anti-Mi-2, Jo-1, PL-7, PL-12 and SRP were positive in 20%, 17%, 2%, 4% and 30% of cases, respectively. No patient had anti-EJ or anti-OJ.Among the MAA, anti-Ku, anti-PM-Scl75, anti-PM-Scl100 and anti-Ro-52 were positive in 20%, 13%, 20% and 44% of cases, respectively.ANA were positive in 87% of cases, of which only 28% were at a strong title ≥1/800. Anti-ENA, anti-DNA, ATPO, Athy and RF were positive in 33%, 7%, 41%, 15%, and 37% of cases, respectively.Three patients (6%) had no antibodies.ConclusionsWe report a high prevalence of MSA in Tunisian patients with IIM, especially anti-SRP. Furthermore, the presence of several MAA might be related to associated autoimmune diseases but can also reflect a particular autoimmune profile in these patients.Disclosure of InterestNone declared