重型再生障碍性贫血患者外周血调节性T细胞的数量异常及其临床意义

Abnormal Quantity of Regulatory T Cells in Peripheral Blood of Patients with Severe Aplastic Anemia and Its Clinical Significance

本研究旨在探讨调节性T细胞(Treg)在重型再生障碍性贫血(SAA)患者免疫失衡中的意义。采用流式细胞术检测44例SAA患者(初治25例、缓解19例)及23名健康对照者外周血CD4+CD25+CD127dimTreg数量,分析其与T细胞亚群(CD4+/CD8+比值)、树突细胞(DC)亚群(mDC/pDC比值)和白细胞(WBC)、网织红细胞百分比(Ret%)表达的相关性。结果表明,初治组CD4+CD25+CD127dim占外周血淋巴细胞(PBL)比例为(0.83±0.44)%,明显低于SAA患者恢复组(2.91±1.24)%(P<0.05)及对照组(2.18±0.55)%(P<0.05),而恢复组与对照组比较差异无统计学意义(P>0.05)。初治组CD4+/CD8+比值为(0.5±0.3)明显低于恢复组(1.2±0.4)(P<0.05)及对照组(1.11±0.24)(P<0.05)。初治组mDC/pDC比值为(3.08±0.72)明显高于恢复组(1.61±0.49)(P<0.05)及对照组(1.39±0.36)(P<0.05)。SAA患者CD4+CD25+CD127dim/PBL与CD4+/CD8+比值呈正相关(r=0.695,P<0.01),而与mDC/pDC比值呈负相关(r=-0.796,P<0.01);SAA患者CD4+CD25+CD127dim/PBL与外周血WBC计数及RET%呈正相关(r=0.761,P<0.01;r=0.749,P<0.01)。结论:SAA患者外周血CD4+CD25+CD127dimTreg占淋巴细胞百分比降低,是引起免疫耐受被破坏、T细胞功能亢进,进而导致造血功能衰竭的机制之一。

This study was purposed to investigate the role of regulatory T cells （Treg） in the immune unbalance for patients with acquired severe aplastic anemia （SAA）. The flow cytometry was used to detect the quantity of CD4 ＋ CD25 ＋ CD127＋m Tregs, T cell subset（ CD4 ＋/CD8 ＋ ratio）, dendritic cell（DC） subset（ mDC/pDC ratio） in 44 SAA patients（25 untreated patients and 19 recovery patients） and 23 normal controls. The correlation between Tregs and T cell subset, DC subset and hemogram were analyzed. The results showed that the percentage of CD4 ＋ CD25 ＋ CD127＋m Tregs in peripheral blood lymphocyte（PBL） of untreated patients was （0.83 ± 0.44）% , which was obviously lower than that in recovery patients （ 2.91 ± 1.24） % and normal controls （ 2.18 ±- 0.55 ） % （ P 〈 0.05 ）, but the difference was not statistically significant between latter two groups. The ratio of CD4 ＋/CD8＋was （0.5 ± 0.3 ） in untreated patients, which was obviously lower than that in recovery patients （ 1.2 ＋ 0.4） and normal controls （ 1.11 ＋ 0.24） （ P 〈 0. 05）. The ratio of mDC/pDC was （3.08 -± 0.72） in untreated patients, which was significantly higher than that in recovery patients（ 1.61 ± 0.49 ） and normal controls （ 1.39 ± 0. 36 ） （ P 〈 0.05 ）. The percentage of CD4 ＋ CD25 ＋ CD127＋jm Tregs in PBL positively correlated with CIM ±/CD8 ± ratio （ r = 0. 695, P 〈 0.01 ）, and that negatively correlated with mDC/pDC ratio （ r = - 0. 796, P 〈 0.01 ）. There were significant positive correlations between CD4 ＋ CD25 ± CD127dim Tregs/PBL and WBC, Ret% （ r = 0. 761, 0. 749 respectively, P 〈 0.01 ）. It is concluded that the decrease of CD4 ＋ CD25 ＋ CD127aim Tregs quantity in SAA may be one of mechanisms underlying bone marrow failure resulting from the deterioration of immune tolerance and hyperfunction of T-cells.