Objective:To investigate the effects of Hydroxychloroquine on cell apoptosis in peripheral blood mononuclear cells of systemic lupus erythematosus and its mechanisms.Methods:The peripheral blood mononuclear cells of 30 active SLE patients and 15 healthy persons were separated for cell culture.There were four groups:control group,SLE group and HCQ 5 mg/L and HCQ 25 mg/L group.MTT was used to measure the inhibitory effect.Annexin V/PI flow cytometry was performed to analyze cell apoptosis.Western blot was used to evaluate the expressions of PI3 K,pAKt,mTOR,BCL-2,BAX and caspase-3.Besides,the PBMCs of SLE patients were treated with HCQ 25 mg/L and the PI3K/Akt pathway inhibitor LY294002 20 μmol/L and its cell growth inhibition and apoptosis were observed.Results:Compared with the control group,the cell growth inhibition and apoptosis rate of SLE patients group were significantly increased(P＜0.05);while the cell growth inhibition and apoptosis rate of HCQ 5 mg/L and 25 mg/L were increased significantly than the SLE patients group(P＜0.05).Compared with SLE patients group,the expression levels of PI3K,pAKt,mTOR and BCL-2 of HCQ group were significantly increased while the expression of BAX and caspase-3 decreased significantly (P＜ 0.05).The PI3K/Akt pathway inhibitor LY294002 could block the PBMCs apoptosis of SLE patients.Conclusion:Hydroxychloroquine can promote the PBMCs apoptosis of SLE patients by PI3K/Akt signaling pathways.