To study on the role of IFN-gamma, IL-10, IL-12 and TRAIL in the pathogenesis of RA.The concentrations of IFN-gamma, IL-12, IL-10 and TRAIL in synovium fluid and sera isolated from 46 patients with RA were determined by Sandwich ELISA.The concentrations (ng/L) of IFN-gamma, IL-12 and TRAIL in synovium fluids from the patients were (106.2+/-7.8), (57.7+/-3.5) and (166.5+/-12.3), respectively. The concentrations (ng/L) of these cytokines in sera from the patients were (56.3+/-7.4), (35.1+/-12.7), (69.5+/-8.3) and in sera from the healthy donors (31.1+/-4.4), (25.2+/-2.6) and (41.2+/-4.8). The levels of cytokines mentioned above in synovium fluid from the patients were higher than those in sera from both the patients and the healthy individuals (P<0.05, P<0.01). There was no significant difference of concentration of IL-10 between the patients and the healthy donors.The levels of IFN-gamma, IL-12 and TRAIL in synovium fluid from the patients with RA are higher than those in healthy donors. This result indicates that the pattern of cytokine on course of RA is main of Th1, more typical in synovium fluid than in serum. Analysis of the concentration of IFN-gamma, IL-12, IL-10 and TRAIL in the serum may be useful to diagnosis and bio-immunological treatment of the RA patients correctly.