Hormone regulation of cells differentiation in thymus at pregnancy (review)

The thymus is the central organ of immunity, where the formation of the major effector and regulatory T-lymphocytes subpopulations. Pregnancy accompanied with steroid-induced involution of the thymus. Such hormone-dependent involution of the thymus was observed also under stress, ageing, a number of autoimmune diseases. During pregnancy the placenta produces a lot of biologically active substances including hormones (estriol, human chorionic gonadotropin, kisspeptin, leptin, ghrelin, etc.) with immuno-modulating activity. However, the mechanisms of hormonal regulation of lymphocyte differentiation at thymus in the aspect of pregnancy remained scarcely explored. The review analysed data from literature and the results of our research on the role of hormones produced by the placenta, in the regulation of main subpopulations of lymphocytes, dendritic cell function, differentiation at thymus and immune tolerance formation.