Part E: The Role of Cytotoxic Natural Killer (NK) Cells and Regulatory NK Cells in Pregnancy
- Pp. 578-591 (14)Shigeru Saito, Tomoko Shima, Akitoshi Nakashima and Yi Lin
During the early phases of pregnancy, natural killer (NK) cells are the predominant lymphoid cells in the uterus. Uterine NK (uNK; decidual NK) cells contribute to vascular formation and placentation, and play an important role in induction of tolerance toward the fetus allograft by interaction with regulatory T (Treg) cells, dendritic cells (DCs) and CD14<sup>+</sup> monocytic cells. </p><p> On the other hand, uNK cells have been shown to induce abortion by attacking the fetus or Placenta.We propose that CD25<sup>+</sup>IL-10<sup>+</sup>NK cells play a pivotal role in successful pregnancy and granulysin<sup>+</sup> NK cells attack extra-villous trophoblasts (EVTs), causing their death due to apoptosis. A deeper understanding of the balance between cytotoxic NK cells and regulatory NK cells during pregnancy may increase understanding of normal pregnancy and complicated pregnancy.