γδT滑细胞在获得性纯红细胞再生障碍性贫血发病机制中的作用

本研究检测获得性纯红细胞再生障碍性贫血（acquired pure red cell aplastic anemia，A—PRCA）患者γδT细胞亚群数量和功能变化，探讨16T细胞在A—PRCA发病机制中的作用。对11例经骨髓涂片和活检确诊的A—PRCA患者，给予环胞菌素A和雷公藤多甙治疗；采用流式细胞术检测免疫抑制剂治疗前后患者T细胞亚群和γδT细胞水平；分离患者外周血中单个核细胞并置于舍有10％FCS，PHA10μg／ml，rIL-250U／ml的RPMI1640培养液培养2周，然后用TCRγδ磁珠分选出γδT细胞，在体外与正常人骨髓共同培养，观察对红系、粒系集落生长的影响。结果显示，治疗前组外周血CD3^＋／CD8^＋细胞数较正常对照组升高，CD4^＋／CD8^＋比例倒置（P〈0．05）；治疗前组患者γδT细胞水平有明显升高（P〈0．05）。治疗后，有效组CD3^＋／CD8^＋细胞数下降（P〈0．05），CD4^＋／CD8^＋比值上升（P〈0．01）；γδT细胞水平较治疗前有明显降低（P〈0．05）。从患者外周血分离的γδT细胞体外能抑制正常骨髓红系CFU—E和BFU—E生长，并随浓度的增长抑制作用越明显，而在不同的浓度梯度下对粒系生长无明显影响。结论：A-PRCA患者γδT细胞亚群增高，其在PRCA的发病机制中起了一定作用；体外分离培养的患者γδT细胞可抑制正常红系集落生长，对粒系集落生长影响不明显；环胞素A治疗A—PRCA有较好疗效。

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.