[Immunology of early pregnancy. I. Immunologically competent cells in the endometrium and decidua]

Changes in the proportion of macrophages, granulocytes and subpopulations of lymphocytes in the secretory endometrium and decidua have been reviewed. The decidual transformation and principles of the neutralization of an adaptative response to embryonic tissues as well as the fetal growth promoting decidual factors have been discussed. The immunological response can broadly be divided into two types, cell mediated and humoral. Cell-mediated immune responses involve the activation of macrophages and the induction of macrophages and the induction of cytotoxic CD8+ and CD4+. T cells, whereas humoral immunity is characterized by antibody production. These two arma of the immune response are regulated by distinct subsets of CD4+ helper T cells, termed Th1 and Th2 cells, which secrete different patterns of cytokines. The pregnancy induced possible Th2 prevalence so as role of such factors like PGE2, TGF2, 1.25-(OH)2-Vit. D3, IL-2, progesteron, estrogens and dehydroepiandrosteron have been reviewed.