The Study Of Biological Characteristic In Decidual And Peripheral Blood NK Cells Of Pregnant Women During The Onset Of Normal Labor

Backgroud:Much of our knowledge of physiological mechanism in human parturition has been blurred. We pay close attention to the mechanism of the initiation of human parturition. Understanding the intimate events leading to parturition is critical, and elucidating the processes of initiate normal labor may help us to understand the spontaneous preterm labor, and devise efficacious interventions against it.Although several factors have been proposed to explain or contribute to labor on set. The local immunity of uterus decidua play an important role. Recent research on maternal-fetal interface has been proposed, the main content is composed of maternal uterus deciduas and fetal trophoblast, all kinds of cells and secreted cytokine are composed of special immunological microenvironment on at the maternal-fetal interface. Immunological competent cells (ICC) and a lot of cytokines constitute special immunologic microenvironment at the maternal-fetal interface, which is crucial for embryo implantation and gestational maintenance. Through the study of characteristic with decidual NK, the subset of decidual NK are named as decidual nature killer cells (dNK cell). In pregnancy, NK cells are enriched at sites where fetal trophoblast infiltrates the decidua. The appearance of decidual NK cells suggest that one of the functions of these cells is control of placentation. Histologic studies indicate NK cells are in direct contact with the invading trophoblast. Decidual NK cells mainly distribute in decidua which links fetal and maternal interface. The specific phenotype and function of dNK cells may contribute to keep immunotolerance in fetal-maternal interface, also can they secrete an array of cytokines facilitate decidual blood rebuilding and maintain the balance of Th1/Th2 cytokines. To study the functions and status of dNK cells undoubtedly helps us to comprehend the physiological phenomena of pregnancy.To further shed light on the immunological mechanisms of labor onset, we pay attention on the immune reactions at the maternal-fetal interface and system immunity reactions between normal late pregnant (NLP) women without labor onset (Caesarean sections) and NLP women with labor onset (spontaneous delivery). We study the percentage and the phenotype in the decidua natural killer (dNK) cells and Peripheral blood natural killer (pNK) cells both in CS group and SD Group, investigate the change of Th1/Th2 cytokine levels of decidual mononuclear cells and peripheral blood mononuclear cells in pregnant women with and without labor onset, so that we can investigate whether disturbed local immune reactions and system immunity reactions have relationship with dNK cells and pNK cells of NLP women during labor onset, to futher study the immunological mechanisms of labor onset. To approach the relationship of system and immunologic microenvironment at maternal-fetal interface.Objective:To detect the change of dNK cells and pNK cells, to compare the percentage, phenotype, Th1,Th2 cytokine secretion and cytotocxic action between dNK cells and pNK cells between NLP women without labor onse and NLP women with labor onset. To approach the relationship of system and immunologic microenvironment at maternal-fetal interface during the labor onset. Methods:1. The same pregnant women third-trimester parietalis decidua and peripheral blood were obtained during elective caesarean sections (CS) women (n=20) and spontaneous delivery (SD) women (n=20). Peripheral blood mononuclear cells (PBMC) were centrifugated using a standard gradient sedimentation technique cell suspensions were prepared by an electromechanical dispersal method and centrifugated using a standard gradient sedimentation technique. And percentage and phenotype of dNK cells were detected by flow cytometric analysis.2. To detect the expression of intracellular Th1/Th2 cytokines IFN-γand IL-4 in dNK cells and pNK cells by the flow cytometry.Results:1. Compared to CS women, the deciduas parietalis from SD women were characterized with the increased the percentage of CD3~-D56~+NKcells, CD56~+CD16~+NK cells,CD56~+CD16~-NK cells,CD56~+NKG2D~+NK cells. Whereas no differences were found in the percentage of CD56~+NKG2A~+NK cells.2. Compared to CS women, the PBMC from SD women were characterized with the increased the percentage of CD3~-D56~+NKcells, CD56~+CD16~+NK cells, CD56~+CD16~-NK cells, CD56~+NKG2A~+cells and CD56~+NKG2D~+NK cells.3. The expression of intracellular Th1 cytokines IFN-γand were significantly high in dNK cells in SD women, while the expression of intracellular Th2 cytokines IL-4 and were significantly low in dNK cells in SD women. Conclusions:Decidual NK cells and peripheral NK cells in SD team are the important natural lymphocytes, whose percentage, phenotype, Th1/Th2 cytokine secretion and cytotocxic activity are obviously different from decidual NK cells and peripheral NK cells in CS team, dNK cells and their secreting cytokines compose the center of decidual immunological regulation through development, regulation, receptor expression, biological effect. Abnormal immune responses not only appear in system immunity but also mainly manifest fetal-maternal interface immunity. From the above results, we conclude that dNK cells play an important role in regulating immunological tolerance at fetal-maternal interface and system immunity, and has relationship at maternal-fetal interface during the labor onset.