[The antisynthetase syndrome: a subgroup of inflammatory myopathies not to be unrecognized]

Antisynthetase syndrome (AS) is frequently revealed by interstitial lung disease and arthritis. There are mechanic's hand, Raynaud's phenomenon and anti aminoacyl t-RNA synthetase antibodies. The anti JO-1 antibody is the most frequently identified. We report five cases of antisynthetase syndrome with particular clinical features and good response to corticosteroids.

There are three women and two men with a median age of 59 years at presentation (range: 44-77). Three patients progressively developed AS: the symptoms are dyspnea (three). Raynaud's phenomenon (one), purpura (one) and hyperkeratosis, scaling and fissuring on the lateral sides of the fingers (two). Patients always had skin signs: hyperkeratosis and scaling (five), purpura (one), Raynaud's phenomenon with normal capillaroscopy (two). Lung disease is present in the five cases with interstitial lesions in CT scans (five), trouble of CO diffusion (three/three) and lymphocytic alveolitis (two/two). Moderate muscular disorders are present in five cases (moderate elevated muscular enzyme: five, positive muscle histology: two). Anti-JO-1 antibodies are present in five cases. AS is associated with connective tissue diseases: rheumatoid polyarthritis in one case and Gougerot-Sjögren in three cases. No malignant tumour is associated. Patients have received oral corticosteroid treatment (five/five) with high doses of intravenous perfusions (three/five) with, initially, a good response. For only one patient, immunosuppressive treatment was necessary because of the articular relapse. The interstitial lung disease had a good response to corticosteroids therapy alone in four cases. Because of the relapse during the tapering off of corticosteroids, corticosteroids were increased in one case and immunosuppressive therapy was required in one case.

The prognosis of AS depends of the interstitial lung disease. High doses of corticosteroids are required. In our study, the response to corticosteroids is good. Immunosuppressive agents must be added in severe and progressive form of interstitial lung disease in AS.