Abstract: Objective:To investigate the expression level of serum decoy receptor 3(DcR3) in patients with rheumatoid arthritis(RA),and its clinical significance.Methods:Sixty RA patients and 30 healthy donators were divided into the RA group and control group,respectively,and the RA group were subdivided into the low activity group and activity group according to the disease activity index.The serum levels of DcR3 and IFN-γ in two groups were detected using enzyme-linked immunosorbent assay(ELISA).Results:The levels of DcR3 and IFN-γ in RA group were significantly higher than those in control group(P<0.01).The differences of the serum levels of DcR3 and IFN-γ between activity group,low activity group and control group were statistically significant(P<0.01).The serum levels of DcR3 and IFN-γ in activity group were significantly higher than those in activity group and control group(P<0.01).The serum level IFN-γ in low activity group was significantly higher than that in control group(P<0.01).The serum level of DcR3 in RA patients was positive correlation with the level of IFN-γ(P<0.05).Conclusions:The expression levels of DcR3 and IFN-γ increase in RA patients,and which is positive correlation with the level of IFN-γ.DcR3 may be involved in the pathogenesis of RA,and is related to the disease activity.