中文摘要：

目的测定重型再生障碍性贫血（SAA）患者外周血辅助性T细胞Ⅲ型（Th3）、CD4^＋＋CD25^＋调节T细胞（Tr）数量和血浆中转化生长因子B1（TGF-β1）水平，探索SAA患者细胞免疫耐受被打破的机制。方法用流式细胞术检测20例发病期和10例免疫抑制治疗（IST）后恢复期的SAA患者外周血表达TGF-β1的CD4^＋细胞（Th3）数量；用流式细胞术检测12例新发SAA患者、9例IST后未恢复和10例恢复期SAA患者的Tr数量，并与12名正常对照比较，分析其与CD3^＋CD4^＋、CD3^＋CD8^＋细胞及CD3^＋CD4^＋／CD3^＋CD8^＋细胞比值的相关性；采用ELISA法检测25例SAA患者血浆中TGF—β1水平，分析其与Th3细胞、血小板计数的相关性。结果正常对照组Th3细胞、CD8^＋ TGF-β1^＋细胞及Th3／CD8^＋TGF-β1^＋细胞比值分别为（5．10±0．91）％，（4．93±0．97）％、1．20±0．19；SAA发病组分别为（1．33±0．20）％，（1．72±0．24）％，1．00±0．25，Th3细胞、CD8^＋TGF—β1^＋细胞比例明显下降（P〈0．01和P〈0．05）；SAA恢复组分别为（2．19±0．21）％，（2．07±0．33）％，1．71±0．52，Th3细胞、CD8^＋TGF-β1^＋细胞比例均较SAA发病组升高，但仍明显低于正常对照组（P值均〈0．05）；正常对照组Tr比例为（8．25±1．96）％；新发SAA组为（3．32±0．81）％，明显低于正常对照组；SAA治疗后未恢复组Tr为（7．09±1．84）％，较新发SAA组明显升高（P〈0．05），与正常对照组差异无统计学意义；SAA恢复组Tr为（7．49±1．27）％，较新发SAA组明显升高（P〈0．05），与正常对照组差异无统计学意义；SAA患者Tr与CD3^＋CD4^＋细胞、CD4^＋／CD8^细胞比值呈正相关（r=0．855，P〈0．01；r=0．729，P〈0．01），而与CD3^＋CD8^＋细胞呈负相关（r=-0．488，P〈0．05）；正常对照组血浆TGF-β1水平为（11．06±0．49）μg／L，SAA组为（2．49±0．51）μg?

英文摘要：

Objective To explore the mechanism of autoimmune intolerance in severe aplastic an mia （SAA）. Methods By FACS, the quantity of peripheral TGF-β producing CD4 ^＋ T cells （Th3） in 20 SAA patients at active phase, 10 SAA patients at recovery phase and 12 normal controls were detected. The percentages of peripheral CD4 ^＋ CD25 ^＋regulatory T cells in 12 SAA patients at active phase, 9 non-responded patients after IST, 6 patients at recovery phase and 12 normal controls were counted, and its correlation with the percentages of CD3 ^＋ CD4 ^＋ and CD3^＋ CD8^＋ cells were analyzed. By enzyme linked immunosorbent assay （ELISA）, the serum level of TGF-β1 in 25 SAA patients and 13 normal controls was measured and its corre- lation with peripheral platelets counts was analyzed. Results The percentages of peripheral Th3 cells, CD8 ^＋ TGF-β1 ＋cells and the ratio of Th3/ CD8^＋ TGF-β1 ^＋ in controls were （5.10 ±0.91 ）% , （4.93±0.97）% and 1.20 ± 0.19 respectively, and those in SAA patients at active phase were（ 1.33 ± 0.20 ）%, （1.72 ±0.24） % , 1.00 ± 0.25, respeetively（P 〈 0.01 ,P 〈 0.05 ）. The aforementioned parameters of SAA patients at recovery phase increased to （2.19 ±0.21 ）% , （2.07 ±0.33）% and 1.71±0.52 respectively, but the percentages of Th3 cells and CD8^＋ TGF-β1^＋ were still lower （ P 〈 0.05 ）. The percentage of Th3 cells was decreased in the SAA patients. The percentage of peripheral CD4^＋ CD25^＋ T regulator cells in peripheral blood of controls was （8.25±1.96）%, and that in SAA patients was （3.32 ± 0.81 ）%. The percentages of CD4 ^＋ CD25 ^＋ T cells of 9 non-responded patients and 10 patients at recovery phase were increased to （7.09 ± 1.84 ） % and （7.49 ± 1.27 ） % respectively, being no difference from those of normal controls. The percent- age of CIM ^＋ CD25^＋ T cells of SAA patients was positively related to the percentage of CD3 ^＋ CD4^＋ cells and the ratio of CD3 ^＋ CD4 ^＋ to CD3 ^＋ CD