Immune Cell Populations in the Endometrium

Specialized immunological studies in the diagnostics of idiopathic infertility and recurrent miscarriages have limited applicability, as the role of the immune system in these conditions is not thoroughly understood. In ovulatory cycles, changes occur in the populations of uterine lymphocytes, which may influence the receptivity of the endometrium and the implantation of the embryo. Particularly notable are the changes in natural killer (NK) cells, which reach their peak during the luteal phase and regulate the invasion of the trophoblast. The dominant NK cells exhibit a CD56bright phenotype and differ in cytokine profiles from peripheral blood cells. Cyclical changes also affect macrophages and T lymphocytes; however, it is unclear whether their proportions differ in women with reduced fertility. There is a need to investigate how the composition of lymphocytes in blood influences the p