CD3和CD8免疫反应阳性细胞在人胎回肠的发育

Development of CD3- and CD8-positive cells in human fetal ileum

目的:探讨CD3和CD8免疫反应阳性细胞在人胎回肠淋巴组织发生过程中的分布、定位及发育.方法:收集因故终止妊娠人胎回肠30例,采用免疫组织化学SP法染色显示CD3和CD8免疫反应阳性细胞,用BioMiaspro图象分析软件对免疫反应阳性细胞进行计数,有关数据作统计学分析.结果:9wk,回肠内可见CD3和CD8阳性反应细胞,主要定位于肠壁的结缔组织内,数量较少,散在分布;11wk可见CD3和CD8阳性细胞三五成群分布;17wk,CD3和CD8阳性细胞聚集成群,主要分布于绒毛中轴以及小肠腺之间固有结缔组织,回肠黏膜上皮偶见阳性细胞浸润;18wk,CD3和CD8阳性反应细胞出现在淋巴小结处参与构成淋巴小结;24wk后,CD3和CD8阳性反应细胞数量增多,尤以典型的集合淋巴小结处有较多分布,其中,在28wk数量增加最为明显(P<0.05).CD8和CD3阳性细胞数量之间有较强的正相关关系(r=0.831,P<0.01),CD3阳性细胞在整个发育过程中数量上均较CD8阳性细胞多.结论:人胎肠相关淋巴组织的形成过程中,第9周即有T细胞发育.CD8和CD3阳性T细胞的发育时序基本同步.

AIM： To investigate the distribution, location and growth of CD3- and CD8-positive cells in developing lymphoid tissue of human fetal ileum. METHODS： Thirty samples of human fetal ileum between gestational weeks 9 and 32 were collected. CD3- and CD8-positive cells were identified by immunohistochemistry using the streptavidin-peroxidase method. The positive ceils were counted using BioMias image analysis software, and the data were analyzed using the SPSS11.5 software package. RESULTS： At gestational week 9, there were few CD3- and CD8-positive cells scattered in the connective tissue of the ileal wall. At week 11, these positive cells were distributed in small clusters. At week 17, CD3- and CD8-positive cells gathered together. The majority of positive cells were distributed in the connective tissue of mucosa, while few positive cells infiltrated into the ileal epithelium. At week 18, CD3- and CD8-positive cells were seen in the lymphoid nodules and participated in the organization of lymphoid nodules. After week 24, the number of the two types of positive cells gradually increased with fetal age, reaching the peak at week 28. The distribution of these positive cells were particularly prominent in aggregated lymphoid nodules. A significant positive correlation was noted between the number of CD3- and CD8- positive cells （r = 0.831, P 〈 0.01）. The number of CD3-positive cells exceeded that of CD8-positive cells at all time points. CONCLUSION： CD3- and CD8-positive T cells begin to appear at gestational week 9 when gutassociated lymphoid tissue is forming in human fetus. The development of CD3- and CD8-positive T cells is basically synchronous in human fetal ileum.