Diminished activity of a chemotactic inhibitor in synovial fluids from patients with familial Mediterranean fever.

Synovial fluids from patients with osteoarthritis contain a chemotactic inhibitor that acts by antagonizing the complement-derived chemotactic anaphylotoxin, C5a. The activity of this inhibitor in synovial fluids from patients with several forms of inflammatory arthritis (rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, and gout) were comparable to the activity present in osteoarthritic synovial fluids. In contrast, levels of inhibitory activity in synovial fluids from 9 patients with familial Mediterranean fever were decreased to less than 20% of those found in osteoarthritis fluids. The possibility was considered that the diminished inhibitory activity in fluids from patients with familial Mediterranean fever plays a part in the pathogenesis of the inflammatory attacks characteristic of this disease.