Objective To investigate the relationship between IL-18 and apoptosis in patients with SLE by using testing the changes of IL-18 and soluble Fas/soluble Fas ligand in sera from the patients.Methods 58 patients with SLE were divided into three groups according to their SLEDAI score;sera from 58 patients,and 30 normal controls were tested for IL-18 and sFas/sFasL using ELISA assay.Results The level of IL-18 and sFas in sera from SLE patients was significantly higher than that of normal controls(P0 05).Besides,the increased level of IL-18 was correlated well with the increased level of sFas (?=0 496,P0 5).Conclusion The increased level of IL-18 may result in the elevation of serum sFas/sFasL in patients with SLE.They may play important roles in the pathogenesis of SLE.