To determine the sensitivity and specificity of anti-Jo-1 in systemic sclerosis (SSc) patients with and without myositis.
Methods. Immunoblots on HeLa nuclei were used to screen sera from 554 consecutive connective tissue disease patients. Those who had 45-55-kd bands, all patients with polymyositis/derrnatomyositis (PM/DM), and a random selection of SSc, Raynaud's disease, systemic lupus erythematosus, and rheumatoid arthritis patients were also studied by anti-Jo-1 enzyme-linked immunosorbent assay and by immunoblots on rabbit pooled aminoacyl-transfer RNA synthetase.
Results. Anti-Jo-1 was present only in 8 of the 40 PM/DM patients.
Conclusion. Anti-Jo-1 is specific for PM/DM.
Anti-Jo-1 antibodies are found in polymyositis/ dermatomyositis (PM/DM) patients, especially in those with lung involvement (1). Anti-Jo-1 is directed at histidyl-transfer RNA (tRNA) synthetase (Jo-1 autoantigen), which is a dimer of 50-kd subunits found in the cytoplasm (1,2). Anti-Jo-1 may be detected by double immunodiffusion, immunoblotting, and enzyme-linked immunosorbent assay (ELISA) (3) using an antigen containing Jo-1 and standard positive and negative control sera.
The presence of anti-Jo-1 in systemic sclerosis (SSc) patients has not been examined in large-scale studies. SSc patients frequently present with lung involvement, and, in some cases, with myositis. Therefore, in the present study, we decided to screen our large series of consecutive SSc patients for the Dr.