CD4+CD25+Treg在急性淋巴细胞白血病患者外周血中的表达及其体外实验研究

目的初步探讨CD4 CD25 调节性T细胞(CD4 CD25 regulatory T cells,CD4 CD25 Treg)在急性淋巴细胞白血病(acute lymphocytic leukemia,ALL)患者化疗前及化疗缓解后外周血中的表达水平,并研究患者血清能否诱导外周血CD4 CD25-T细胞转化为CD4 CD25 Treg。方法①采用流式细胞术分别检测ALL初诊组、化疗完全缓解或部分缓解组及正常对照组外周血中CD4 CD25 T细胞所占比例,然后通过荧光定量RT-PCR检测各组外周血中转录因子Foxp3mRNA的表达水平,并逐层分析比较。②采集正常人外周血单个核细胞后,对照组用正常人血清,实验组用患者血清并分别设浓度梯度进行培养,72h后采用流式细胞术、荧光定量RT-PCR分别检测CD4 CD25 T细胞和Foxp3mRNA表达。结果ALL化疗缓解组CD4 CD25 T细胞及Foxp3mRNA表达水平均明显高于ALL初诊组和正常对照组(P<0.05),后两者之间CD4 CD25 T细胞水平无统计学差异(P>0.05),但ALL初诊组Foxp3mRNA含量较正常对照组明显升高(P<0.01),差异具有统计学意义;并且血清培养对照组CD4 CD25 T细胞水平及Foxp3mRNA含量均明显低于实验组(P<0.05),且其表达并不随血清浓度的增加而升高。结论CD4 CD25 Foxp3 Treg在ALL初诊组及化疗缓解组患者外周血中比例明显升高,且初步表明患者血清中的可溶性物质可诱导外周血CD4 CD25 T细胞转化为CD4 CD25 Treg,提示CD4 CD25 Treg可能是ALL免疫抑制的一个重要原因。

Expression of CD4+CD25+ regulatory T cells in the patients with acute lymphocytic leukemia

AIM: To evaluate the proportion of CD4 CD25 Tregs in the peripheral blood of the patients suffering from acute lymphocytic leukemia (ALL) with or without chemotherapy and investigate whether the serum from patients could convert peripheral CD4 CD25-T cells to CD4 CD25 Tregs. METHODS: The proportion of CD4 CD25 T cells in the peripheral blood of three groups of people (the patients with ALL before therapy, the patients with ALL who achieved partial remission (PR) or complete remission (CR) and the healthy donors) was evaluated by flow cytometry. The level of Foxp3 mRNA expression of each group was examined by FQ-RT-PCR. Furthermore mononuclear cells isolated from the peripheral blood of the healthy donors were added to laboratory serum of ALL and control serum of healthy donors respectively. Each group was devided into sub-groups according to various serum doses. After culture for 72 h, the cells of all the groups were harvested separately and further tested for the expression of CD4 CD25 T cells by flow cytometry. The FQ-RT-PCR method was used to examine the expression of Foxp3 mRNA expression. RESULTS: The percentage of CD4 CD25 T cells and Foxp3 in the patients with ALL after chemotherapy was significantly higher than that of the healthy donors and the patients with ALL without chemotherapy. Although the proportion of CD4 CD25 T cells in the patients with ALL without chemotherapy was almost the same with that in the healthy donors, the level of Foxp3 mRNA expression in the former was higher. Moreover, the proportion of CD4 CD25 T cells and the level of Foxp3 mRNA expression in experimental group were statistically higher than those in control group. The expression of Foxp3 mRNA in control group did not vary with the serum dosage. CONCLUSION: The proportion of CD4 CD25 Foxp3 Tregs in the peripheral blood of the patients with ALL with or without chemotherapy is significantly higher than that of healthy donors. The serum derived from the patients with ALL can convert CD4 CD25-T cells to CD4 CD25 Tregs, which might be one of the important reasons for immunosuppression in ALL.