Alteration of CD4~+CD25~+ regulatory T cells and Foxp3 in peripheral blood of aplastic anemia patients and its clinical significance

Objective:To investigate the levels of CD4+CD25+ regulatory T cells(Treg) and Foxp3 in peripheral blood of patients with aplastic anemia(AA),and to explore the clinical significance of Tregs in AA.Methods:The percentage and absolute numbers of CD4+ T cells、CD4+CD25+/ CD4+ and CD4+CD25high / CD4+T cells in peripheral blood monouclear cell(PBMC) were examined with flow cytometry in 25 patients with AA,including 18 patients with non-severe aplastic anemia(nSAA) and 7 patients with severe aplastic anemia(SAA).The expression of Foxp3 in CD4+CD25+,CD4+CD25low and CD4+CD25high T cells was analyzed by flow cytometry.The levels of Foxp3 mRNA in PBMC were determined by RT-PCR.Results:Compared with those of normal controls,the percentage and absolute numbers of CD4+ T cells,CD4+CD25+/ CD4+ and CD4+CD25high / CD4+T cells were decreased in patients with AA(P0.05),especially in patients with SAA(P0.001).The percentage of Foxp3+ in CD4+CD25+,CD4+CD25low and CD4+CD25high T cells in patients with AA was lower than that in normal controls(P0.05).However,the levels of Foxp3 mRNA was not significantly changed in AA patients(P0.05).Conclusion:These findings suggest that the decrease of Tregs in patients with AA might be related to the incidence of AA.The absilute numbers of Tregs in SAA patients are lower than that in nSAA,which can provide hints for evaluation of disease progression.