Clinical characteristics and literature review of myopathy with positive anti-signal recognition particle antibody / 中风与神经疾病杂志

ABSTRACT

@#To investigate the clinical characteristics of myopathy with positive anti-signal recognition particle （SRP） antibody. Methods The clinical data，laboratory examination，diagnosis and treatment of 4 patients with anti-SRP antibody positive myopathy were retrospectively analyzed. Results Four patients had different onset modes and could have chronic onset. The main manifestations were proximal limb weakness and dysphagia，significantly increased serum creatine kinase and positive serum anti-SRP antibody. Electromyography （EMG） suggested myogenic damage，but may also be accompanied by some neurogenic damage. Myocardial enzyme and transaminase elevated in some patients. Muscle pathology showed degeneration，necrosis，and regeneration of skeletal muscle fibers. Hypertrophic and atrophic muscle fibers were involved in both types. Inflammatory cells may be present，mainly macrophages，with a small infiltration of lymphocytes. Expression of major histocompatibility complex class 1（MHC-I）was diffusely positive or weakly positive，and membrane attack complex （C5b-9） staining showed complement deposition of necrotic muscle fibers. Conclusion Anti-SRP antibody positive myopathy is an important type of immune-mediated necrotizing myopathy with a variety of clinical manifestations. The diagnosis mainly depends on the detection of anti-SRP antibody in blood and muscle pathology. If it can be identified early，the administration of early sufficient dose and long-term effective maintenance dose of drug therapy can improve the prognosis.