肌炎特异性自身抗体(MSAs)对于肌炎的诊断、分型、疗效评估和预后判断均有重要的指导意义。虽然十七种MSAs已被鉴定，但是这些抗体的总阳性率仅为50-60%，因此仍然有自身抗体尚未被发现。本课题组通过高通量的自身抗原芯片的筛查，发现15例肌炎患者的MSAs检测均为阴性。本课题拟采用自身抗原芯片结合非放射免疫沉淀法继续筛查肌炎患者人群的自身抗体谱，进一步筛选抗体阴性的血清样本。进一步采用含9000个蛋白质的芯片、骨骼肌或肺裂解液，在自身抗原芯片筛查为抗体阴性的肌炎患者血清中寻找新自身抗体，通过免疫层析纯化和质谱分析鉴定新自身抗原，并研究其在肌炎患者人群中的阳性率和相关的临床表现。开展本项目，可望促进肌炎的精准诊治和预后判断，并发现新的肌炎特异性自身抗体，为肌炎的诊断和疾病分型提供新的思路。

Myositis specific autoantibodies have been extensively demonstrated to be important biomarkers for myositis, aiding in diagnosis, helping to classify patients into more homogeneous groups, predicting additional clinical complications and response to treatment. Untill now seventeen kinds of myositis specific autoantibodies have been identified in about 50% -60% of patients with myositis, which means that a number of novel myositis autoantibodies need to be investigated. Our study had found that 15 patients with myositis were screened as negative for all known myositis specific autoantibodies using autoantigen microarray. The present study will continue to screen for autoantibodies profile in chinese cohort with myositis using autoantigen microarray combined with non-radiolabelled immunoprecipitation . For the serums with negative autoantibodies, the protein microarray or muscle lysate or lung lysate will be used to identify novel myositis autoantibodies. The novel myositis autoantigens will be confirmed by immunoaffinity purification and mass spec. The prevalence and associated clinical features of novel myositis autoantigens will be investigated in patients with myositis. The aim of the present study is to find more biomarkers including the differentially expressed genes, serum cytokines and novel myositis autoantigens for aiding in diagnosis, subsets, predicting response to treatment and prognosis for myositis.