LAUSR

Studies in autoimmune inflammatory myositis (AIM) have shown a strong role of autoantibodies in the diagnosis and prognosis of patients with myositis. This ongoing study shares the preliminary data of 139 patients with AIM from a North Indian tertiary care centre. This prospective, observational study was conducted at a 1250-bedded hospital to assess the prevalence of myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) in patients from the Indian subcontinent with AIM and the correlation of these antibodies with clinical features. From November 2016 to September 2022, patients with AIM (satisfying the Bohan and Peter criteria of 1975) attending the Rheumatology and Clinical Immunology Department of Medanta Hospital were included after taking their informed consent, and divided into subgroups as dermatomyositis (DM), polymyositis (PM), CTD-associated myositis (CTD-M), cancer-associated myositis (CAM), and juvenile myositis (JM). The Institutional Ethics Committee approved the study. Clinical data and sera from patients were collected and analysed. The study included 139 individuals with a mean age of 45.4 years. Fifty-two had DM, 49 had PM, 25 had CTD-M, 6 had CAM, and 7 had JM. ANA positivity was found in 67.70%, MSA in 22.3%, MAA in 25.4%, and both in 12.3%. Antibodies against Mi-2 were identified in 13 (28.9%) patients, Jo-1 in 14 (32.50%), PL-7 in 3 (6.7%), PL-12 in 4 (8.9%), SRP in 9 (20%), and MDA-5 and NXP2 in 1 (2.2%) patient each. Antibodies against Ro were found in 28 (57.1%) of the patients, RNP in 8 (16.3%), and PM-Scl in 9 (18.4%). Mi-2 antibodies were mostly identified in DM patients and were significantly associated with skin rash. SRP positivity was mostly found mainly in PM. Raynaud's and ILD were linked to the presence of Jo-1 and Ro antibodies. Malignancy screening was negative in NXP2 and TIF1γ antibody-positive patients. MSA was found in 22.3% of cases and MAA in 25.4%. Mi-2 antibodies were linked to rash, but none had ILD, whereas Jo-1 antibodies were linked to mechanic hands, arthritis, and ILD. We aim to gather more strong results in the future as additional patients are recruited in this continuing trial. Disclosure S. Dhuria: None. P. Khatri: None. N. Negalur: None. K. Telang: None. S. Ghosh: None. D. Yadavalli: None. V. Singal: None. R. Gupta: None.