Flt3 ligand promotes T cells proliferation and expansion of T_H1 in patients with aplastic anemia
Objective To investigate the influence of Flt3 l igand (FL) on T cell polarization and its relationship to hematopoiesis failure in patients with aplastic anemia(AA). Methods T helper su bsets were identified by flow cytometry according to different cytokines from T cells and enzyme-linked immunoadsorbent assay(ELISA) was employed to determine the l evel of IFN-γ and IL-10 in supernatant. The influences of PHA and cytokines o n T cell polarization were also investigated. Results The proportion of T H1 in the peripheral blood(PBL) and bone marrow(BM) of AA pati ents increased, especially in those with serious AA(P0.01). The balance be tween the T H1 and T H2 was broken and the ratio of T H1/T H2 was higher in AA patients when compared with controls(2.1±0.8 and 1.4±0.7, P0.05). The proportion of T H1 didn′t change when isolated T cells were incubation with P HA and IL-2. But the number of T H1 significantly increased and the concentrat ion of IFN-γ also increased when normal BM cells were cultured in medium conta ining of FL. Besides T H1 cells, the proportion of dendritic cells and NK cells increased in comparison with controls. Conclusion High l evels of FL in AA patients promoted T cells to differentiated toward T H1 cell type and was one reason to explain the bone marrow failure in patients with AA.