الفهرس 
Review of LiteratureOnly 14 pages are availabe for public view
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Abstract
reeclampsia is the most frequently encountered medical complication of pregnancy. It is characterized by the new onset of hypertension and proteinuria, usually during the last trimester of pregnancy, and is commonly associated with edema and hyper uricemia (Sibai et al., 2005). The placenta plays a central role in the pathogenesis of preeclampsia,as evidenced by the rapid disappearance of clinical signs and symptoms of preeclampsia following delivery of the placenta. Preeclampsia is characterized by widespread systemic vascular endothelial dysfunction and microangiopathy in the mother, but not in the fetus (Karumanchi et al., 2005).
Although defective placental trophoblastic invasion and dysfunction of maternal vascular endothelium are significant in the pathogenesis of preeclampsia, maladaptive or altered immune response is also believed to play an important role in this pregnancy disorder. Exaggerated inflammatory response, imbalance of Th1/Th2 cytokine generation (Jonnson et al., 2006), and aberrant interaction of maternal leukocytes and placental trophoblasts at the maternal-fetal interface (Chaouat et al.,2005) are all considered to be the crucial components of the altered immune response during preeclampsia6
In preeclampsia, the shift away from type1 responses either fails to occur or is reversed, with increased production of IL-18 and IFN relative to normal pregnancy (Germain et al., 2007). This type1bias can be seen in T cells (Saito et al., 2007) and more predominantly in NK or NK like T (Borzychowski et al., 2005).
Natural killer cells are large granular lymphocytes that are not of T cell or B cell lineage that express CD16 and CD56, but do not express CD3.The function of natural killer cells is direct killing of virus-infected cells and production of cytokines, providing a rapid but relatively nonspecific response to infection. They also appear to play a role in immune surveillance against the development of metastatic spread of certain tumors and in preventing inappropriate hematopoiesis outside of the bone marrow (Vince et al., 2002).
NK cells make up 5–10% of peripheral blood lymphocytes (PBL) and 70–90% of uterine lymphocytes and are distinguished from other cell types by the expression of NK-specific surface markers, i.e., CD56–positive cells. Human NK cell subsets exist as either CD56bright or CD56dim NK cells. In addition, CD56bright cells are mainly found in the decidua. In peripheral blood, the main population of NK cells consists of CD56dim cells. The regulation of uterine and circulating peripheral blood NK cells may be associated with reproductive disorders such as recurrent pregnancy loss (RPL), implantation failure and preeclampsia (Fukui et al., 2011) The immunological interaction between the mother and fetus has classically been thought of as one between paternal antigen and maternal T cells. However, the MHC antigen expression on human trophoblast and the immune cell populations present in the decidua suggest that this interaction primarily involves decidual NK cells rather than T cells, and this is supported by new functional studies. It is becoming apparent also that the maternal systemic immune response in pregnancy (Th1/Th2 shift) primarily involves NK cells. Aberrant NK cell activation both locally in the decidua and systemically in the maternal blood may be the cause of pre-eclampsia (Sargent et al., 2007).
To characterize NK cells CD56+ profiles in normal pregnancy and preeclampsia, this case control study was designed to determine whether abnormal levels of CD56+cells in maternal serum correlate with the diagnosis of preeclampsia. Eighty patients with preeclampsia were enrolled in the study group and eighty normal pregnant women served as control. All subjects were nulliparous Egyptian women. Maternal age was similar between the two groups. Blood samples were taken from each participant after taking informed concent for determination of CD56+ cells levels in maternal serum by Io test conjugated antibody technique. In this study,it was found that, CD56 levels were significantly higher in the preeclampsia group than the control group with sensitivity 94% specificity 51% PPV 57% and NPV 96%.
Also we found that there is inverse relation between gestional age and CD56 NK cells.