Objective: 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/dermatomyositis (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.