Anti-Jo-1 antibody: a marker for myositis with interstitial lung disease.

An autoantibody known as anti-Jo-1 antibody is found in 25% of patients with myositis. Its prevalence in patients with both myositis and cryptogenic fibrosing alveolitis was 68% (13 out of 19 patients), compared with 7.5% in patients with myositis alone (four of 53) and 3% in patients with cryptogenic fibrosing alveolitis alone (two of 62). Anti-Jo-1 antibody may be useful in indicating patients with myositis and cryptogenic fibrosing alveolitis. Raynaud's phenomenon, the sicca syndrome, and mild arthritis are also often part of the syndrome.