Expression Of CD4～+CD25～+regulatory T Cells In Patients With Acute Leukemia And Study Them Ex Vivo

Aim: To evaluate the proportion of CD4~+CD25~+ Tregs in peripheral blood of the patients of AL with or without chemotherapy and investigate whether the serum from patients could convert peripheral CD4~+CD25-T cells to CD4~+CD25~+ Tregs. It maybe provide a new method to treat diseases.Methods: Firstly ,The population of CD4~+CD25~+ T cells in the peripheral blood of the patients with AL before therapy ,AL who achieved CR and of the healthy donors was evaluated by flow cytometry.Furthermore,Foxp3mRNA expression levels of each group were examined by real-time-fluorescence quantitative retroverse trascriptase polymerase chain reaction (FQ-RT-PCR).Secondly Mononuclear cells isolated from the peripheral blood of healthy donors was added with laboratory serum of ALL and control serum of healthy donor respectively .Each group was designed into sub-groups according to various serum dose .After culture for 72 hours ,the cells of all 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 examined the expression level of Foxp3 mRNA.Results: The percentages of CD4~+CD25~+T cells and Foxp3 in AL after chemotherapy were significantly higher than those of the healthy donors and AL without chemotherapy(P<0.01). Although the population of CD4~+CD25~+T cells in AL without chemotherapy was almost the same to that in the healthy donors(P>0.05),the expression of Foxp3 mRNA in former was higher(P<0.01). And the percentages of CD4~+CD25~+T cells and the Foxp3 mRNA levels in AL did not vary with the sub-types of AL. Furthermore, the proportion of CD4~+CD25~+T cells and the expression levels of Foxp3 mRNA in experiment group were statistically higher than those in control group(P<0.05) .And which also did not vary with the serum dose.Conclusion: The population of CD4~+CD25~+Tregs in peripheral blood of AL with or without chemotherapy was significantly higher than that of healthy donors. Furthermore, we also investigated that the serum derived from ALL could convert CD4~+CD25-T cells to CD4~+CD25~+Tregs, as might be one of the important reasons of immunosuppression in AL.