Abstract:Objective To analyze the prevalence of myositis specific autoantibodies (MSAs) and myositis associated autoantibodies (MAAs) and their clinical correlations in the patients with idiopathic inflammatory myopathies (IIMs) in Hainan. Methods A total of 78 IIMs inpatients confirmed in the Second Affiliated Hospital of Hainan Medical University from January 2018 to March 2021 were selected. By immunoblotting, the prevalence of MSAs and MAAs were detected to analyze their correlations with clinical data in all patients. Results According to the latest EULAR/ACR classification criteria, 33% of patients in this cohort were identified as suspicious IIMS. Polymyositis (PM) was the most common clinical subtype of IIMs. MSAs was found in 82.1% of patients. The most frequently detected autoantibodies were anti-Jo-1(41.0%) and anti-SRP (25.6%). Among the four clinical subgroups of IIMs, anti-MDA5 positivity was significantly associated with amyopathic dermatomyositis (ADM), which presented severe lung damage, especially in rapidly progressive pulmonary disease and was correlated with classic dermatomyositis (DM) rash. The anti-synthetase antibodies (ASAs) was correlated with arthritis and interstitial lung disease (ILD). The anti-signal recognition particle (anti-SRP) positive rate (25.6%) was 90.0% of PM patients, and was related with serum creatine kinase (CK), lactate dehydrogenase (LDH) and dysphagia. The positivities of anti-nuclear matrix protein 2 (NXP2) and anti-transcription intermediary factor 1 (TIF1-γ) were low, appearing in 1 case of pathologically diagnosed as cholangiocarcinoma. The positive anti-Ro-52 (56.4%) in the most common detected MAAs (61.5%) was associated with arthritis and mechanic’s hands. Anti-Ro-52 was significantly correlated with anti-Jo-1. Conclusion MSAs and MAAs appear in the majority of IIMs patients and are related to clinical subtypes and clinical charactereristics. Therefore, MSAs may play an important role in the diagnosis, treatment and prognosis of IIMs.