[Expression of blood Th17 and CD4(+) CD25(+) Treg cells in patients with aplastic anemia].

This study was aimed to investigate the expression of blood Th17 and CD4(+) CD25(+) regulatory T cells (Treg) in the patients with aplastic anemia (AA). Forty-five patients with AA were enrolled into this study, and were divided into mild aplastic anemia (MAA) group (n = 25) and severe aplastic anemia group (SAA) (n = 20), blood cell count was recorded. 15 healthy donors were enrolled as control. Proportions of blood Th17 and CD4(+) CD25(+) Treg cells were determined by flow cytometry. The serum levels of IL-17, IFN-γ and TNF-α, as well as their concentrations in culture supernatant of phytohemagglutinin (PHA) -stimulated peripheral blood mononuclear cells, were measured by ELISA. The results showed that the proportions of blood Th17 cells and concentration of blood serum IL-17 and IFN-γ increased in patients with SAA, compared with MAA and normal controls, but CD4(+) CD25(+) Foxp3(+) Treg cells obviously decreased in patients with SAA. The concentrations of IL-17 and IFN-γ significantly increased in culture supernatant of SAA group. Hemoglobin level in the patients with AA negatively correlated with the population of Th17 cells and serum IL-17 level, whereas positively correlated with the expression of CD4(+) CD25(+)Treg cells. It is concluded that the increased response of Th17 cells and deficiency of CD4(+) CD25(+) Treg cells present in severe aplastic anemia. The severity of anemia may be related with the imbalance between Th17 and CD4(+) CD25(+)Treg cell response.