CD4^＋CD25^highT细胞在特发性血小板减少性紫癜发病机制中的作用

本研究探讨特发性血小板减少性紫癜（ITP）治疗前后患者外周血中CD4^＋CD25^highT细胞（CD25-PE染色阳性〉10^2为CD4^＋CD25^highT细胞）的表达情况及其可能的作用机制。应用免疫荧光标记和流式细胞术检测20例治疗前ITP患者、20例治疗后患者及14名正常人外周血中CD4^＋CD25^highT细胞的表达。结果表明：ITP患者治疗前外周血T细胞表面CD4^＋CD25^highT细胞表达水平明显低于治疗后组及正常对照组（P均〈0．01）；ITP治疗后患者组与正常对照组相比无显著性差异（P〉0．05）。结论：ITP治疗前患者外周血中CD4^＋CD25^highT细胞水平较正常对照组明显降低，而在治疗有效后有所升高。外周血CD4^＋CD25^highT细胞表达率与血小板数量呈正相关。CD4^＋CD25^highT细胞水平的检测可作为对ITP患者预后判断的一个有效指标，并可以作为免疫治疗的靶点进行进一步研究。

Role of CD4(+) CD25(high) T Cells in the Pathogenesis of Idiopathic Thrombocytopenic Purpura

This study was aimed to investigate the expression level of CD4(+) CD25(high) T cells in peripheral blood of patients with idiopathic thrombocytopenic purpura (ITP) before and after treatment and to explore its significance in pathogenesis of ITP. The expressions of CD4(+) CD25(high) T cells in peripheral blood of 20 ITP patients before treatment, 20 ITP patients after treatment and 14 normal individuals (control) were detected by immunofluorescence and flow cytometry. The result showed that the expression of CD4(+) CD25(high) in ITP group before treatment was evidently lower than that in treated ITP group and control (p < 0.01), but there was no remarkable difference between the treated ITP group and the control group p > 0.05). In conclusion, the expression of CD4(+) CD25(high) T cells in the ITP group before treatment was evidently lower than that in the control group, which becomes higher than before when the patients showed effective respone to the treatment. Correlation of CD4(+) CD25(high) T cell expression rate in peripheral blood with platelet level was positive. Therefore the expression level of CD4(+) CD25(high) T cells can be used as an effective index to judge the ITP prognosis. Further study of CD4(+) CD25(high) T cells regarded as an immune target is needed.