大剂量地塞米松对特发性血小板减少性紫癜患者B细胞活化因子及调节性T细胞的影响

目的 研究大剂量地塞米松治疗前后特发性血小板减少性紫瘕(ITP)患者B细胞活化因子(BAFF)和调节性T(Treg)细胞的变化.以及BAFF对Treg细胞的作用.方法 用ELISA方法 检测21例慢性活动性ITP患者治疗前后血浆BAFF水平;用流式细胞术检测患者治疗前后及外周血单个核细胞培养体系中Treg细胞的比例.结果 治疗前ITP患者的BAFF水平[(599.70±199.40)pg/ml]较正常对照[(454.50±132.50)pg/ml]明显升高(P<0.05),Treg细胞比例明显降低[(1.56±6.73)%](P<0.01);大剂量地塞米松治疗后,ITP患者的BAFF水平[(296.9±119.7)pg/ml]较治疗前明显下降(P<0.01),且低于正常对照组(P<0.01);Treg细胞比例明显升高[(5.94±2.22)%](P<0.01),且高于正常对照[(4.08±1.08)%](P<0.01).ITP患者BAFF水平和Treg比例与血小板计数无相关性(P>0.05).体外实验显示,rhBAFFO组和rhBAFF20组Treg数量无明显改变(P>0.05).结论 慢性ITP患者的BAFF水平增高,Treg细胞数量减少.大剂量地塞米松可降低患者的BAFF水平,增加Treg细胞的数量.BAFF对Treg细胞无明显影响.

Effect of high-dose dexamethasone on BAFF and Tregs in patients with immune thrombocytopenic purpura

Objective To investigate the change of B-cell activating factor of the TNF family (BAFF)and regulatory T-cells(Tregs)before and after high-dose dexamethasone(HD-DXM)therapy and assess the effect of BAFF on Treg cells in immune thrombocytopenic purpura(ITP).Methods The plasma BAFF concentration was measured by ELISA.and Treg cell numbers by flow cytometry.Results The plasma BAFF level[(599.70±199.40)pg/m1]was significantly increased(P<0.05),and the percentage ofTreg cells[(1.56±0.73)%]was significantly decreased(P<0.01)in ITP patients before treatment ascompared with that in controls[(454.5±132.5)pg/ml and(4.08±1.08)%,respectively].After treat-ment with HD-DXM,the plasma BAFF level[(296.9±119.7)PS/m1]was significantly decreased(P<0.01),and the percentage of Treg cells[(5.94±2.22)%]was significantly increased(P<0.01).The BAFF level and Treg proportion had no significant correlation with platelets count(P>0.05).In in vitroassays,no difference was found in the number of Treg cells between rhBAFF0 group and rhBAFF20 group[(1.53±0.69)%,(1.49 4-0.67)%,P=0.89)].Conclmion BAFF level was increased and Treg cellsdecreased in ITP patients.HD-DXM might play a role in ITP treatment by down-regulating BAFF expressionand up.regulating Treg cells number.BAFF had no influenee on the number of Treg cells.