Department of Obstetrics and Gynecology, Shiga University of Medical Science.
Tohoku J Exp Med. 2020 Jan;250(1):49-60. doi: 10.1620/tjem.250.49.
The uterus is an organ for raising the fetus, and its lumen is lined by the endometrium. The endometrium is an important site for the implantation and maturation of fertilized eggs. The endometrium undergoes repetitive proliferation, maturation (decidualization), and exfoliation changes every menstrual cycle. At the same time, the number and type of endometrial immunocompetent cells vary during the menstrual cycle. At the implantation stage, the immunocompetent cells occupy approximately half of the endometrial cells. Immunocompetent cells normally eliminate pathogenic microorganisms to protect the body; however, they also promote immune tolerance to accept the fetus during pregnancy. The immunocompetent cells in the uterus can perform both these functions. With the establishment of pregnancy, stimuli from the trophoblast (placenta) and fetus can also change the immune environment of the uterus, and pregnancy can be maintained only when the immune system is well adapted to the stimuli of some hormones and the fetus. Immunity for the establishment of pregnancy is not simple because multiple immunocompetent cells are involved in establishing and maintaining pregnancy. To understand the immune mechanisms associated with the establishment of pregnancy, we have to learn about each immune cell. This review, therefore, discusses the roles and distribution of the immunocompetent cells inside the uterus during menstruation and early pregnancy.
子宫是孕育胎儿的器官，其腔内衬有子宫内膜。子宫内膜是受精卵着床和成熟的重要部位。子宫内膜在每个月经周期中经历反复的增殖、成熟（蜕膜化）和脱落变化。同时，子宫内膜免疫活性细胞的数量和类型在月经周期中也会发生变化。在着床阶段，免疫活性细胞大约占据子宫内膜细胞的一半。免疫活性细胞通常会消除致病微生物以保护身体，但在怀孕期间，它们也会促进免疫耐受以接受胎儿。子宫中的免疫活性细胞可以同时执行这两种功能。随着妊娠的建立，滋养层（胎盘）和胎儿的刺激也可以改变子宫的免疫环境，只有当免疫系统很好地适应一些激素和胎儿的刺激时，妊娠才能维持。妊娠的建立免疫并不简单，因为涉及多种免疫活性细胞来建立和维持妊娠。为了了解与妊娠建立相关的免疫机制，我们必须了解每种免疫细胞。因此，这篇综述讨论了在月经和早孕期间子宫内免疫活性细胞的作用和分布。
