【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)、CD+ CD25+调节T细胞(Tr)数量和血浆中转化生长因子β1(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／L,较正常对照组明显下降(P<0．01);SAA组血浆TGF-β1水平与Th3细胞呈正相关(r=0．396,P<0．05),与血小板水平呈正相关(r=0．701,P<0．01)。结论SAA患者外周血Th3细胞、Tr数量和血浆中TGF-β1水平下降可能导致SAA患者细胞免疫耐受被打破。更多还原

【Abstract】 Objective To explore the mechanism of autoimmune intolerance in severe aplastic anemia (SAA). Methods By FACS, the quantity of peripheral TGF-βproducing 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 correlation 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, respectively (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 percentage of CD4+ CD25+ T cells of SAA patients was positively related to the percentage of CD3+ CD4+ cells and the ratio of CD3+ CD4+ to CD3+ CD8+ , but negatively to the percentage of CD3+ CD8+ cells. The percentage of CD4+ CD25+ T cells was decreased in the SAA patients. The plasma level of TGF-β1 in normal controls was (11.06±0.49)μg/L, and that in SAA patients was (2. 49±0. 51)μg/L (P <0. 01). The plasma level of TGF-β1 in SAA patients was positively related to the percentage of Th3 cells and the platelet counts (P < 0. 05, P < 0.01). Conclusion The percentages of peripheral Th3 and CD4+ CD25+ T cells, and the plasma level of TGF-β1 in SAA patients were decreased, which break down the autoimmune tolerance in SAA.更多还原