[Anti-SRP myopathy]

Detection of autoantibodies can provide more important clinical information in assigning patients to clinical subsets, selecting a therapy and predicting prognosis. Muscle biopsy is the principal examination for a diagnosis of myositis; however, autoantibody detection is also useful. Myositis-associated autoantibodies, detected in 30% of myositis patients, can be screened by RNA immunoprecipitation assay. Some case series have revealed that the anti-SRP antibody, detected in 5-8% of polymyositis patients, was generally associated with severe and refractory polymyositis. However, it has been accepted that anti-SRP myopathy should be separated from polymyositis based on histological and clinical features. Some patients with anti-SRP myopathy show chronic progression indistinguishable from muscular dystrophy.