NK Cells and Pregnancy

Natural killer cells are found in large numbers in the endometrium and decidua, and data suggest that NK cell functions and interactions with fetal-derived trophoblasts can have a profound impact on pregnancy. Altered NK cell numbers and activity have been associated with a variety of clinical conditions such as endometriosis, recurrent pregnancy loss, and preeclampsia. Uterine NK cells have a unique phenotype compared to blood NK cells and this is likely due to the specific tissue environment in which they reside. Specific chemokines produced by human endometrium and trophoblasts have been identified that may be responsible for recruitment of NK cells. Uterine NK cells can produce cytokines and may be an important part of vascular remodelling during placenta! development. This chapter summarizes current knowledge of NK cells in the uterus and their role in pregnancy and reproductive disorders.