H Hanaoka1, Y Kaneko1, S Suzuki2, T Takada1, M Hirakata1, T Takeuchi1, M Kuwana1,3. 1. a Division of Rheumatology, Department of Internal Medicine , Keio University School of Medicine , Tokyo , Japan. 2. b Department of Neurology , Keio University School of Medicine , Tokyo , Japan. 3. c Department of Allergy and Rheumatology , Nippon Medical School Graduate School of Medicine , Tokyo , Japan.
Abstract
OBJECTIVES: To clarify the prevalence of anti-signal recognition particle (anti-SRP) antibody in connective tissue diseases (CTDs) and investigate the clinical characteristics of patients without inflammatory myopathy. METHOD: Sera from 6180 patients with CTD were examined by immunoprecipitation (IPP) assays, and the records of patients positive for anti-SRP antibody were reviewed retrospectively. The antibody against the 54-kDa protein of SRP (SRP54) was quantified by enzyme-linked immunosorbent assay (ELISA) in patients with anti-SRP antibody. RESULTS: Of the 28 patients positive for anti-SRP antibody, nine (32.1%) did not have inflammatory myopathy. The clinical diagnoses and characteristics of those patients varied considerably. In patients with inflammatory myopathy, the index of anti-SRP54 was much higher than in those without myopathy (1.15 vs. 0.46; p = 0.036). CONCLUSIONS: The prevalence of anti-SRP antibody was 0.5% in a cohort of Japanese patients with CTD, and one-third of them did not have inflammatory myopathy. Sera from patients with inflammatory myopathy recognized SRP54 more strongly than in those without myopathy.
OBJECTIVES: To clarify the prevalence of anti-signal recognition particle (anti-SRP) antibody in connective tissue diseases (CTDs) and investigate the clinical characteristics of patients without inflammatory myopathy. METHOD: Sera from 6180 patients with CTD were examined by immunoprecipitation (IPP) assays, and the records of patients positive for anti-SRP antibody were reviewed retrospectively. The antibody against the 54-kDa protein of SRP (SRP54) was quantified by enzyme-linked immunosorbent assay (ELISA) in patients with anti-SRP antibody. RESULTS: Of the 28 patients positive for anti-SRP antibody, nine (32.1%) did not have inflammatory myopathy. The clinical diagnoses and characteristics of those patients varied considerably. In patients with inflammatory myopathy, the index of anti-SRP54 was much higher than in those without myopathy (1.15 vs. 0.46; p = 0.036). CONCLUSIONS: The prevalence of anti-SRP antibody was 0.5% in a cohort of Japanese patients with CTD, and one-third of them did not have inflammatory myopathy. Sera from patients with inflammatory myopathy recognized SRP54 more strongly than in those without myopathy.