[Anti-synthetase syndrome: a special subgroup of idiopathic inflammatory myopathies. Apropos of 3 case reports].

Anti-synthetase antibodies are found in 20 to 25% of all idiopathic inflammatory myopathies and allow identification of a syndrome associating myositis with interstitial pulmonary disease (50 to 70%), polyarthritis, Raynaud's phenomenon and mechanic's hands. Anti-Jo-1 is the most common anti-synthetase antibody. If anti-Jo-1 is present, interstitial lung disease must be looked for, because this is the most important determinant of the outcome. Treatment with high doses of corticosteroids is required. Immunosuppressive drugs are added in resistant cases or as corticosteroid-sparing agents.