调节性T细胞及Foxp3基因在再生障碍性贫血患儿外周血中的变化及意义

Expression of regulatory T cells and Foxp3 gene in peripheral blood of children with aplastic anemia

目的研究CD4+CD25+CD127low调节性T细胞(Treg)及Foxp3基因在再生障碍性贫血(简称再障)患儿外周血中的表达水平,探讨其在再障发病机制中的作用。方法采用流式细胞术分别检测21例慢性再障(CAA)、9例急性再障(SAA)和15例健康儿童(对照组)外周血Treg细胞的比例变化,并用RT-PCR方法检测其外周血中Foxp3mRNA的表达水平。结果SAA和CAA组患儿外周血中CD4+T细胞百分比、CD4+CD25+、CD4+CD25+CD127lowTreg细胞占CD4+T细胞百分比均低于对照组(P<0.05),且SAA组低于CAA组(P<0.05);相关基因FoxP3mRNA在SAA患儿外周血中呈低表达(0.47±0.08)%,明显低于对照组(0.71±0.12)%和CAA组(0.68±0.14)%,P<0.05。结论再障患儿外周血Treg细胞和Foxp3mRNA表达减低,可能在再障的发病过程中有重要作用,且SAA表达低于CAA,有望用于再障病情严重程度的评估。

Objective To investigate the levels of CD4＋CD25＋CD127low regulatory T cells （Tregs） and the expression of Foxp3 gene in peripheral blood of children with aplastic anemia （AA） and to study their roles in the pathogenesis of AA.Methods Twenty-one children with chronic AA,9 with acute AA and 15 healthy children were enrolled.The proportion of CD4＋CD25＋ CD127low Tregs in CD4＋ T cells was evaluated by flow cytometric analysis.The level of Foxp3 mRNA was ascertained by RT-PCR.Results The percentage of peripheral blood CD4＋T cells and CD4＋CD25＋ and CD4＋CD25＋CD127low Tregs in CD4＋T cells in both the acute and chronic AA groups was significantly lower than that in the normal control group （P﹤0.05）.The acute AA group had more decreased CD4＋ T cells and CD4＋CD25＋ and CD4＋CD25＋CD127low Tregs percentage compared with the CAA group （P0.05）.The expression of Foxp3 mRNA in peripheral blood decreased obviously in the acute AA group （0.47±0.08%） compared with that in the normal control （0.71±0.12%） and the CAA groups （0.68±0.14%） （P0.05）.Conclusions The low expression of Tregs and Foxp3 mRNA in peripheral blood may be involved in pathogenesis of AA.The more decreased Tregs and Foxp3 mRNA expression in acute AA than chronic AA suggests their possible roles in the assessment of the severity of AA.