Abstract： Objective This study explored the change of IL-18,and IFN-γ and their role in the pathogenesis of primary Sj(o)gren's syndrome (pSS) by determining the expression of IL-18,IFN-γ in labial glands and blood of patients with pSS.Methods The levels of IL-18,IFN-γ in labial glands of patients with pSS were determined by immunohistochemical method.The level of serum IL-18 was determined with enzyme linked immunosorbent assay ELISA.The level of γ globulin was measured by the cellulose acetate membrane method.SPSS 17.0 statistical software was used for data analysis.The t test,Fisher's exact probability test and index correlation analysis were performed with linear correlation analysis.Spearman's test was used to examine the association between the expression of IL-18 and IFN.Results The positive rate of IL-18 and IFN-γ in patients with pSS was much higher than normal control group(P＜0.05).And the IL-18 and IFN-γ levels were positively correlated with patients with pSS (P＜0.05).The level of serum IL-18 in patients with pSS was (216±85) pg/ml,which was much higher than normal control group (39±8) pg/ml.The IL-18 level and γ globulin (23.2±2.6)％ was positively correlated in patients with pSS (r=0.538,P＜0.05).Conclusion The expression of IL-18 and IFN-γ in labial glands of patients with pSS are much higher in patients with pSS than those of the normal controls.The results have shown that IL-18 and IFN-γ may be involved in the pathogenesis of pSS.