[Role of gammadeltaT cells in pathogenesis of acquired pure red cell aplastic anemia]

This study was purposed to investigate the changes in quantum and function of gammadelta T cell subsets, and to explore its significance in pathogenesis of acquired pure red cell aplastic anemia (A-PRCA). Eleven patients were diagnosed as A-PRCA based on bone marrow smear and biopsy, and were treated with cyclosporine A and glucosidorum tripterygll totorum. The flow cytometry technique was used for analyses of T cells subsets and gammadelta T cells. Furthermore, peripheral mononuclear cells (MNC) isolated from A-PRCA patients were cultured in RPMI 1640 medium (10(5) cells/ml) containing 10% FCS, phytohemagglutinin (PHA, 10 microg/ml), and recombinant human interleukin-2 (rIL-2, 50 U/ml) for two weeks, then gammadelta T cells were isolated with the TCRgammadelta Microbead Kit from cultured cells. The collected gammadelta T cells were incubated with normal control bone marrow MNC in RPMI 1640 medium (37 degrees C, 5% CO2 atmosphere) for CFU-E, CFU-GM, and BFU-E colony assay. The result showed that compared with the control group, CD3(+), CD8(+) cells increased significantly in the patient group (P < 0.05), the CD4(+)/CD8(+) ratio decreased and reversed, and gammadelta T cells were significantly increased in patient group (P < 0.05). After treatment with cyclosporine A, 9 out of 11 patients got good response, and CD3(+), CD8(+) cells in the responding patient decreased, the ratio of CD4(+)/CD8(+) returned to normal, and gammadelta T cells also decreased to normal range. Moreover, in vitro culture, the gammadelta T cells isolated from A-PRCA patients showed an inhibiting action to CFU-E and BFU-E but not to CFU-GM in a dose-dependent manner. It is concluded that gammadelta T cells increase in A-PRCA patients, and decrease in parallel to normal range with significant improvement of anemia symptoms after immune suppressive therapy. The gammadelta T cells isolated from A-PRCA patients showed an inhibiting action to CFU-E and BFU-E but not to CFU-GM in vitro culture, suggesting that gammadelta T cells may bring an impact on the research of A-PRCA pathogenesis. Cyclosporine A demonstrated better therapeutic effect on A-PRCA patients.