[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.

Citrate in synovial fluid and its relation to inflammation and crystal presence.

Objective: To investigate the role of citrate in the pathophysiology of arthritides with calcium pyrophosphate dihydrate (CPPD) crystals and/or apatite-like material.

Methods: We measured citrate concentrations in the plasma and synovial fluid (SF) of 23 joints whose SF contained these crystals and 33 joints without crystals. The SF originated from 25 joints each of patients with rheumatoid arthritis (RA) and primary osteoarthritis (OA) and 10 patients with various other inflammatory joint diseases.