Part G: Human Uterine Natural Killer Cell: Friends or Foes of Pregnancy Outcomes
Pp. 360-376 (17)
Eliana M.O. Lippe, Aureo T. Yamada and Surendra Sharma
The successful embryo implantation and development in humans and rodents
are dependent on a tightly choreographed dialogue between maternal and fetal milieu,
involving cross talking cells, cytokines and hormones. This dialogue involves the
endothelial cells, stromal cells and leukocytes in the endometrium from the maternal
side, and trophoblast cells from the embryo side culminating into a complex signaling
network. Unscheduled deregulation of these signals could result in pregnancy
complications. An intriguing aspect of this dialogue is the participation of uterine
Natural Killer cells (uNK), a lymphocyte population that accumulates in the uterine
microenvironment specifically during pregnancy. uNK cells differ from their peripheral
blood counterparts both in humans and rodents by virtue of high granule content, low
cytotoxicity, and production of cytokines. Although there have been suggestions for the
involvement of NK cells in programming of early pregnancy loss, a debate still
continues to assess their role as a friend or a foe to pregnancy. In this chapter, we
discuss the importance of phenotypic and functional aberrations and their association
with abnormal pregnancy outcomes.
Uterine Natural killer cells, angiogenesis, cytotoxicity.
Department of Pediatrics, Women and Infants Hospital- Warren Alpert Medical School of Brown University, Providence, Rhode Island 02912, USA.