SYNOVIAL-FLUID CONCENTRATION OF 5 DIFFERENT CYTOKINES IN RHEUMATIC DISEASES

Interleukin-1,, interleukin-2, tumour necrosis factor a, and the interferons, alfa and gamma, were measured concurrently in synovial fluid samples from 68 patients with rheumatic diseases. Mean interleukin-1r concentrations (130.3 (SD 22) pg/mI) were higher in synovial fluids from patients with rheumatoid arthritis (RA) than in those from patients with osteoarthritis (27-8 (4.5) pg/ml), while measurements in synovial fluids from patients with seronegative spondarthritis were intermediate (72-7 (32) pg/ml). Interleukin-2 and tumour necrosis factor a concentrations were lower in the inflammatory arthropathies (RA: 4-5 (0.6) U/mI, 0.39 (0.04) ng/ml; seronegative spondarthritis: 3-1 (0.3) U/ml, 0-33 (0-03) ng/ml respectively) than those in patients with osteoarthritis (5-2 (0.6) U/mI; 0.05 (0.04) ng/ml). Interleukin-2 and tumour necrosis factor a concentrations correlated in all groups (r=0-7), as did the interferons alfa and gamma (r=0-7). There was no relation between interleukin- l6 and either interleukin-2 or tumour necrosis factor a, or between the interferons and any other cytokine. Several distinct cytokine patterns were noted. Synovial fluids from two non-arthritic subjects were also examined: interleukin-l,B concentrations were low, but concentrations of the other cytokines were higher than those seen in most arthritic fluids.