Necrotizing myopathy with anti-signal recognition peptide antibodies: a clinical and pathological analysis of five cases / 中华神经医学杂志

ABSTRACT

Objective To investigate the clinical and pathological features of necrotizing myopathy with anti-signal recognition particle antibodies and its treatment.Methods Five patients with necrotizing myopathy with anti-signal recognition particle antibodies,admitted to our hospital from March 2011 to July 2012,were chosen in our study; their clinical and pathological manifestations and treatment methods were retrospectively analyzed.Results Five patients showed clinical manifestations of subacute onset,proximal limb muscle weakness.Serum creatine kinase level was significantly elevated.Immunoblotting confirmed positive signal recognition particle antibodies.EMG prompted myogenic damage.Pathology manifested as muscle degeneration,necrosis with regeneration,visible atrophy and hypertrophy of muscle fibers,and connective tissue hyperplasia,and no significant inflammatory cell infiltration was noted.Immunohistochemistry staining showed necrotizing muscle fibers infiltrated with CD4-positive T lymphocytes and CD68-positive macrophages,no CD8-positive T lymphocytes and CD20-positive B lymphocytes.Sarcoglycans staining,dystrophine staining and dysferlin staining showed continuous strong positive expression.Follow-up found patients were poor response to glucocorticoid,and a combination therapy of immunosuppressive agents was better than hormone alone.Conclusion The prominent manifestations of necrotizing myopathy with anti-signal recognition particle antibodies are symmetric proximal muscle weakness,with highly elevated levels of serum creatine kinase; fiber necrosis and regeneration are the main myopathlogical features,without obvious inflammatory cells infiltrates; this disease is poorly responsive to corticosteroids and immunosuppression.