Expression of myositis specific autoantibodies in polymyositis/dematomyositis and other neuromuscular diseases

Objective To investigate sensitivity and specificity of myositis specific autoantibodies (MSAs) in polymyositis/dematomyositis(PM/DM ) and other neuromuscular disease. Methods Taking serum from 63 patients with PM/DM (PM/DM group)and 60 definite neuromusclar disease(non-myositis) patients(control group). All the sera were detected for two kind autoantibodies:anti-Jo-1,anti-SRP by immunoblotting method. Calculating sensitivity,specificity of anti-Jo-1 and anti-SRP autoantibodies for the diagnosis PM/DM. Results Positive ratio for anti-Jo-1 and anti-SRP autoantidodies were 17% and 5% respectively in the PM/DM group, while none of the sera from control group detected positive.The specificity of both autoantibodies diagnosis for PM/DM were 100% and (95% CI:94%~100%).The sensitivity was 22%( 95%CI:13%～34%). Conclusion Anti-Jo-1 and anti-SRP autoantibodies are highly specific to PM/DM diagnosis.