Myopathy with antibodies to the signal recognition particle: report of 8 cases / 中华风湿病学杂志

ABSTRACT

ObjectiveWe report the clinical and pathological features of 8 Chinese myopathy patients with antibodies to the signal recognition particle(SRP).MethodsSerum myositis antibody profiles were tested with immunoblotting.Muscle biopsies were performed for histological,enzyme histochemical and immunohistochemical stainings.The first antibody in the immunohistochemical staining was mouse anti-human monoclonal antibodies including CD8,CD20,CD68,MHC- Ⅰ and CD31.ResultsEight cases showed stark positive of anti SRP antibody,3 of them with positive anti Ro-52 antibody.The muscle biopsies showed necrotic and regenerative muscle fibers associated with infiltration of macrophage,but scattered T lymphocytes in 2 patients.Two of them presented with fiber hypertrophy and proliferation of connective tissue.There were some fibers with positive MHC-Ⅰexpression.Capillaries were almost normal.Conclusion The muscle weakness of myopathy with antibodies to SRP presents as a chronic progressive course and could associate with lung involvement.Fiber necrosis and regeneration are the main myopathological features,which can mimic muscular dystrophy in some cases.