INTERRELATIONSHIPS BETWEEN INTERLEUKIN (IL)-1, IL-6 AND IL-8 IN SYNOVIAL-FLUID OF VARIOUS ARTHROPATHIES

High levels of many cytokines, including interleukin (IL)-1, IL-6 and IL-8, were found in various arthropathies suggesting that they play a role in the pathogenesis of disease, although their relationship with the type and activity of disease is still not clear. The synovial flui d (SF) of 24 patients with rheumatoid arthritis (RA), 19 with psoriati c arthritis (PA) and 33 with osteoarthritis (OA) was analyzed for IL-1 beta, IL-6 and IL-8. The highest concentration of the three cytokines was found in the SF of RA. IL-beta detectable levels (greater than or equal to 20 pg/ml) were observed in 8/24 (33.3%) patients with RA, in one patient with PA but in no patient with OA. IL-6 (mean +/- SD) (16 10.37 +/- 1781.65 pg/ml) was higher in RA than in PA (672.47 +/- 867.4 0 pg/ml, p = 0.043) and OA (89.45 +/- 120.52 pg/ml, p = 0.0001). IL-8 (1042.72 +/- 698.64 pg/ml) was higher in RA than in PA (660.36 +/- 625 .11 pg/ml, p = 0.03) and OA (89.9 +/- 45.88 pg/ml, p = 0.0001). A corr elation between IL-1 beta, IL-6 and IL-8 was found in RA. In all patie nts a correlation between IL-6 and IL-8 levels was found; moreover, th ese two cytokines were associated with SF indices of inflammation, suc h as white blood cells (WBC) count and total protein (TP) concentratio n. Our findings suggest that these interrelationships play a role in t he evolution of more severe erosive arthropathy such as RA.