人胎肠系膜淋巴结组织发生及相关T、B细胞的发育

Histogenesis of the mesenteric lymph nodes and development of related T and B cells in human fetus

目的:从形态学的角度探讨人胎肠系膜淋巴结组织发生及相关T、B细胞的发育。方法:收集人胎33例,测量顶臀长,按Patten法确定胎龄。采用常规组织学H-E染色、免疫组织化学法,观察人胎肠系膜淋巴结组织发生及相关T、B细胞的发育。结果:9周,人胎肠系膜淋巴结原基形成,IgM阳性细胞出现,散在分布;11周,出现CD3阳性细胞,原基中有高内皮微静脉;15周,形成早期髓质;23周,IgM阳性细胞集聚形成小结状。连续切片显示,CD3阳性细胞分布在小结深面形成薄层副皮质区,可辨认皮质和髓质;至28周时,淋巴小结内均未发现生发中心。结论:9周淋巴结原基出现。15周早期髓质形成,髓质形成早于皮质。23周皮、髓质明显可辨,皮质内出现淋巴小结,但至28周时小结仍为初级淋巴小结;9周出现B细胞;11周出现T细胞。

Objective： To study the histogenesis of the mesenteric lymph nodes and development of related T and B ceils in the human fetuses, Methods： 33 human fetuses from 9 to 28 weeks of gestation were collected. The crown-rump length of the fetuses was surveyed and the age of the fetuses was determined with the method of Patten. Hematoxylin- Eosin staining, immunohistochemical method were used in this study. Results： At embryonic week 9, the primordium of the mesenteric lymph nodes were formed, and IgM positive cells occurred singly. Two weeks later, CD3 positive ceils occurred and high endothelial venules （HEVs） were observed in the primordiums of the mesenteric lymph nodes. The premier medullas were seen at 15 weeks of fetal age. At 23 weeks, IgM positive cells were gathered and nodule-like structures were formed. CD3 positive cells were distributed in the deep surface of the nodules and formed thin layer paracortex. The cortex and medulla would be recognized, but the germinal centers yet would not be observed until to 28 weeks. Conclusion.. （1） The primordium of the mesenteric lymph nodes occurs at embryonic week 9. The medullas appears at 15 weeks initially and ahead of the cortex. The medullas find cortex can be distinguished clearly until to 23 weeks, when the lymphoid nodules within the cortex develops, even though it maintains to primary lymphatic nodules up to 28 weeks. （2） B cells present at embryonic week 9 and prior to T cells by 2 weeks.