重型再生障碍性贫血患者CD8＋效应T细胞损伤骨髓造血途径的研究

Effect of CD8 ＋ effector T cells on the hematopoiesis pathway damage in the patients with severe aplastic anemia

目的研究重型再生障碍性贫血（SAA）患者外周血CD8＋CD25＋和CD8＋HLA—DR＋T细胞数量及其杀伤靶细胞的途径，探讨SAA的免疫发病机制。方法应用流式细胞术检测29例SAA（初治14例、缓解15例）患者及12名健康对照者外周血CD8＋CD25＋和CD8＋HLA—DR＋T细胞的数量及其胞质内穿孔素、颗粒酶B、肿瘤坏死因子B（TNF—β）、胞膜FasL表达。结果SAA初治组患者CD8＋CD25＋T细胞占CD8＋和CD3＋T细胞的比例分别为（3．67±2．58）％和（2．25±1．35）％，缓解组为（5．19±4．29）％和（2．98±1．35）％，正常对照组为（4．84±2．31）％和（2．11±1．88）％，CD8＋CD25＋T细胞占CD8＋和CD3＋T细胞的比例三组间比较差异无统计学意义（P值均〉0．05）。初治组CD8＋HLA-DR＋T细胞占CD8＋T细胞比例为（39．30-4-8．13）％，缓解组为（20．65±5．38）％，正常对照组为（18．34±6．68）％，初治组明显高于缓解组及正常对照组（P〈0．01），缓解组与正常对照组比较差异无统计学意义（P〉0．05）。SAA初治组CD8＋HLA-DR＋T细胞占CD3＋T细胞比例为（27．81±7．10）％，缓解组为（12．02±3．03）％，正常对照组为（8．50±2．33）％，初治组明显高于缓解组及正常对照组（P〈0．01），缓解组明显高于正常对照组（P〈0．05）。SAA初治组CD8＋HLA—DR＋T细胞穿孔素、颗粒酶、TNF—β、FasL中位表达比例分别为8．51％、96．08％、72．11％、94．25％，均明显高于缓解组（1．78％、85．20％、34．38％、51．20％）及正常对照组（1．86％、82．09％、17．92％、32．91％）（P值均〈0．05），缓解组与正常对照组比较差异无统计学意义（P〉0．05）。结论SAA患者外周血CD8＋HLA—DR＋效应T细胞比例增加，CD8＋效应T细胞影响靶细胞的穿孔素-颗粒酶途径、细胞因子（TNF—β）途径、Fas／FasL途径均参与了骨髓造血细胞损伤的过程。

Objective To investigate the quantity and the pathway to damage hematopoietic cells of CD8 ＋ CD25 ＋ and CD8 ＋ HLA-DR ＋ effector T cells in peripheral blood （PB） of severe aplastic anemia（SAA） patients and explore the immunopathogenesis of SAA. Methods The quantity of CD8 ＋ CD25 ＋ and CD8 ＋ HLA-DR＋ cells in PB and the expressions of perforin, granzyme B, tumor necrosis factor-β （TNF-β） and FasL in 29 SAA （ 14 untreated and 15 recovered） patients and 12 normal controls were analyzed by flow cytometry. Results The fraction of CD8 ＊ CD25 ＋ T cells in CD8 ＋ T cells was （ 3.67 ± 2.58 ） % in untreated SAA patients, （5.19 ± 4.29）% in recovered patients and （4.84 ± 2.31 ）% in normal controls, and that of CD8 ＋CD25＋T cells in CD3 ＋ cells in the three groups was （2.25±1.35）%, （2.98 ±l.35）＋/o and （2.11±1.88 ） % , respectively. They had no statistic difference among the 3 groups （ P 〉 0.05 ）. The fraction of CD8 ＋ HLA-DR ＋ T cells in CD8 ＋ T cells was （ 39.30 ± 8.13 ） % in untreated patients, which was significantly higher than that in recovered patients [（20.65 ± 5.38 ） % ] and controls [ （ 18.34 ± 6.68 ） % ]（P 〈 0. 001 ）, while there was no statistic difference between the latter two groups （ P 〉 0.05 ）. CD8 ＋ HLA DR＋T cells in CD3 ＋ cells was （27.81 ± 7.10）% in untreated group, which was significantly higher than that of recovered group [ （ 12.02±3.03 ） % ＋ and controls [ （8.50± 2.33 ） % ] （P 〈 0.01）. And that in recovered group was higher than that in eontrol group （ P 〈 0. 05 ）. The expressions of perforin, granzyme B, TNF-β and FasL of CD8＋ HLA-DR＋ T cells in untreated group were 8. 51%, 96.08% , 72. 11% and 94.25% respectively, which were higher than those in recovered group（ 1.78%, 85.20%, 34.38% and 51.20% ） and controls（ 1.86% , 82.09% , 17.92% and 32.91% ）. There was no statistie difference between recovered patients and controls （P 〉 0.05 ）. Conclusion There were elevated quantity of CD8 ＋ HLA-DR ＋ T cells and high expressions of perforin, granzyme B, TNF-13 and FasL in SAA, which might contribute to the bone marrow failure.