CD8^+调节性T细胞在ITP发病中的意义及大剂量地塞米松的影响

The role of CD8^+ regulatory T cell and the effect of high-dose dexamethasone in patients with immune thrombocytopenia

目的:研究大剂量地塞米松治疗前后免疫性血小板减少症(ITP)患者体内CD8^+ 调节性T细胞(Treg)及相关细胞因子的变化,了解CD8^+ Treg在ITP发病中的意义及大剂量地塞米松的影响。方法:流式细胞仪分析初诊ITP患者大剂量地塞米松治疗前后CD8^+ Treg的变化,ELISA法检测患者治疗前后血浆转化生长因子(TGF)-β1和白细胞介素(IL)-10的水平。结果:治疗前ITP患者CD8^+ T细胞亚群中的CD8^+ CD28^-Treg,尤其是CD8^+ CD25^+ Foxp3^+ Treg细胞比例较正常对照明显下降,血浆TGF-β1和IL-10的水平明显降低;大剂量地塞米松治疗后,获得缓解的ITP患者的CD8^+ CD28^- Treg及CD8^+ CD25^+ Foxp3^+ Treg细胞比例较治疗前明显升高,而与正常对照比较差异无统计学意义;血浆TGF-β1和IL-10的水平亦明显升高。结论:在初诊ITP患者CD8^+ T细胞亚群中,CD8^+ Treg细胞比例减少,获得缓解后CD8^+ Treg细胞比例增加,说明CD8^+ Treg参与了ITP的发病过程,增加CD8^+ Treg细胞比例和上调血浆TGF-β1和IL-10的水平可能是大剂量地塞米松发挥作用的机制之一。

Objective：To investigate the change of CD8^＋ regulatory T cell （Treg） and cytokines before and after treatment with high-dose dexamethasone,and assess the role of CD8^＋ Treg and the effect of high-dose dexamethasone in patients with immune thrombocytopenia （ITP）. Method： The cell numbers of CD8^＋ Treg were analyzed by flow cytometry. The plasma levels of TGF-β1 and IL-10 were measured by ELISA. Result： The percentage of CD8^＋CD28^- Treg, especially CD8^＋ CD25^＋ Foxp3^＋ Treg was significantly decreased in ITP patients when compared with controls,and the plasma levels of TGF-β1 and IL-10 were significantly lower compared with controls. After high-dose dexamethasone treatment, the percentages of CD8^＋ CD28^- Treg and CD8^＋ CD25^＋ Foxp3^＋ Treg were significantly higher than that in ITP patients with remission. The plasma levels of TGF-β1 and IL-10 in patients with remission were also increased after treatment. Conclusion： These findings suggest that reduced CD8^＋ Treg might contribute to the pathogenesis of ITP, and that elevated level of TGF-β1 and IL-10 and up-regulated CD8^＋ Treg might contribute to the therapeutic effect of high-dose dexamethasone in the treatment of ITP.