Expression Of Chemokines In The Early Pregnancy Uterus And Its Significance

Pregnancy is a complex physical process, which is similar to organ transplantation in immunology and requires that the maternal immune system, in defiance of all known laws of transplantation, tolerates the presence of a conceptus expressing paternal antigens. The materal-fetal immune equipoise is the foundation of successful human pregnany.These immune cells, termed "decidual granulated leukocytes", are composed predominatedly (70%) of the natural killler (NK) cells, accompanied by T cells (15%) and macrophages (15%). The phenocyte of 90% uNK is CD56^birghtCD16^- and only 10% is CD56^dimCD16⁺. Uterine NK (uNK) cells accumulate in the stroma, preferably around glands and vessels as single cells or aggregates. The percentage of uNK cells change during the menstrual cycle and pregnancy. uNK cells account for about 10% of stromal cells in the prolifirative phase, 20% in the secretory phase and 30% of endometrial stromal cells in early pregnancy (decidua).uNK cells are capable of producing a wide range of molecules such as interferon (IFN)- γ , macrophage colony-stimulating factor(M-CSF), and vascular endothelium growth factor(VEGF) that are important for the embryo implantation and early placentation.These NK cells also play important immune inhibitory function by the complex receptor system on their surface. Immunology study of the NK cells gene knockout animals and pathological pregnancy concluded that NK cells missing would lead to pathological pregnancy even abortion directly. For example, the number of CD56^brightCD16^- uNK cells in recurrent pregnancy loss (RPL) women decrease compared with the control.The mechanism underlying the recruitment of endometrial NK cells remains unknown completely now. Chemokines are a group of small peptides (8-12kDa) that induce the migration of leukocytes into normal, inflammatory, and tumor tissues by binding to a family of seven-transmembrane G protein-coupled receptors. Chemokines are classified into four subgroups (C, CC, CXC, and CX3C) by the spacing of the first two-conserved cysteine residues of these proteins. Chemokine receptors are members of a class of seven-...