胎儿及新生儿脐带血T淋巴细胞表型的比较研究

Comparative study of the phenotype of T lymphocyte of cord blood of human fetus and term birth

目的探讨胎儿及足月新生儿外周血 T淋巴细胞表型的演变。方法通过 B超定位穿刺获得不同孕周正常胎儿脐带血 ,并分离其 T淋巴细胞 ,与同期获得的孕足月脐带血及孕妇外周血 T淋巴细胞 ,均予荧光抗体双标 ,流式细胞仪分析各组 T淋巴细胞表面分子 ;分析胎儿 T淋巴细胞表型与孕龄的关系 ,并对比研究胎儿与成人 T淋巴细胞表型之差异。结果随着胎龄增加 ,胎儿外周血白细胞中淋巴细胞百分率逐渐下降 ;T淋巴细胞中 CD4 + /CD8+比率亦逐渐下降 ;胎儿 CD3 +TCRγδ及 CD4 5 RO阳性细胞群显著低于成人外周血相应百分率。胎儿脐血中 CD3 4 +细胞百分比明显高于成人外周血。结论胎儿 T淋巴细胞表型与孕龄有关 ,与成人外周 T淋巴细胞相比 ,具有不成熟性 。

ObjectiveTo study the phenotype differentiation of the T lymphocytes in normal human fetal umbilical cord blood Methods The samples were taken during the early second trimester to third trimes ter using the advanced ultrasound guided cordocentesis technique, and c ompared with that obtained from term fetuses and of adult peripheral blood samples Analysis of immuno phenotype and sub population of T lymphocytes was performed by flow cytometry ResultsThe percentage of lymphocytes in the white blood cell population gradually decreased wi th the increase of the gestational ages The ratio of CD4 +/CD8 + also gradually decreased The sub populations of the CD3 + TCR γδ + and CD45RO + cells of fetuses were significantly smaller than t hose found in adult peripheral blood The frequency of CD34 + cell s of fetuses is significantly higher than that found in adult periphe ral blood Conclusion The percentage o f lymphocyte content decreases gradually from the second trimester to term pregnancy The phenotype of the T lymphocyte differentiates as t he gestational age increases The immature phenotype and sub populatio n of fetal cord blood compared with that of adult peripheral blood m ay be associated with the way the fetus gain its immune tolerance