Clinical features and prognosis of patients with idiopathic inflammatory myopathies and anti-Jo-1 antibodies

The idiopathic inflammatory myopathies are a heterogeneous group of diseases that can involve various systems. Antibodies directed against aminoacyl-tRNA synthetases, such as anti-Jo-1 antibodies, are strongly associated with a syndrome which consists of myositis, interstitial lung disease (ILD), arthritis and Raynaud's phenomenon. Forty-one patients with various forms of idiopathic inflammatory myopathies were assessed: 14 patients with anti-Jo-1 antibodies and 27 patients without anti-Jo-1 antibodies as a control group. We retrospectively analysed clinical symptoms, treatment and outcome in both groups. Patients without the anti-Jo-1 antibodies more often had ILD (64.2 vs. 11.1%), arthritis (64.2 vs. 18.1%) and Raynaud's phenomenon (38 vs. 0%). Patients without the anti-Jo-1 antibody presented worse muscle strength and more frequently myalgia (37 vs. 21%), cutaneous rash (18.5 vs. 7%), heliotrope rash (29% vs. 7%) and periungueal changes (22 vs. 0%) than the anti-Jo-1-positive patients. Outcome was good in both groups. Improvement was achieved in the 14 (100%) Jo-1 positive patients, and in 25 (92.5%) controls. Two (7.5%) patients from control group achieved remission.