[Determination and clinical significance of serum anti-ryanodine receptor antibody in patients with myasthenia gravis].

Objective: To explore the clinical significance of serum anti-ryanodine receptor (RyR) antibody in the diagnosis of myasthenia gravis (MG).
Methods: The crude sarcoplasmic reticulum was prepared from rabbit skeletal muscle, and then purified by differential centrifugation to produce the antigen. The serum anti-RyR antibody levels in 74 patients with MG (including 21 patients with comorbidic thymomas) were determined with ELISA.
Results: Western blot demonstrated the presence of RyR in purified crude sarcoplasmic reticulum. The positive rate of anti-RyR antibody was significantly higher in MG patients who had comorbidic thymoma compared with those who had no such comorbidity (P < 0.01). Also, the positive rate was closely correlated with the severity of MG.
Conclusion: Serum anti-RyR antibody test is helpful in the diagnosis of MG associated with thymoma and can be used to judge the outcome of MG.