ACCUMULATION OF SOLUBLE FAS IN INFLAMED JOINTS OF PATIENTS WITH RHEUMATOID-ARTHRITIS

Objective. To examine the concentration of the soluble form of the Fas molecule (sFas) in the serum and synovial fluid of patients with rheu matoid arthritis (RA) and osteoarthritis (OA). Methods. The concentrat ion of sFas in the serum of 15 normal subjects and in the synovial flu id and serum of 45 RA patients and 13 OA patients was determined, The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and the level of several cytokines in serum and synovial fluid were al so determined. Results. The synovial fluid concentration of sFas was h igher in RA than in OA patients (P < 0.005), The synovial fluid level of sFas correlated weakly with serum levels of CRP (r = 0.541), the ES R (r = 0.499), and with synovial fluid levels of interleukin-2 (IL-2) receptor (r = 0.544), IL-6 (r = -0.529), and intercellular adhesion mo lecule 1 (r = 0.514), Reverse transcription-polymerase chain reaction analysis revealed that synovial cells and infiltrating mononuclear cel ls expressed sFas messenger RNA in RA patients. Conclusion. Our data s uggest that accumulation of sFas in the joint cavity of RA patients ma y inhibit apoptosis and exacerbate the inflammatory process.