Natural killer cells and pregnancy

Nat Rev Immunol. 2002 Sep;2(9):656-63. doi: 10.1038/nri886.


The fetus is considered to be an allograft that, paradoxically, survives pregnancy despite the laws of classical transplantation immunology. There is no direct contact of the mother with the embryo, only with the extraembryonic placenta as it implants in the uterus. No convincing evidence of uterine maternal T-cell recognition of placental trophoblast cells has been found, but instead, there might be maternal allorecognition mediated by uterine natural killer cells that recognize unusual fetal trophoblast MHC ligands.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Female
  • Fetus / immunology
  • Humans
  • Immune Tolerance
  • Immunity, Innate
  • Killer Cells, Natural / immunology*
  • Major Histocompatibility Complex / immunology
  • Models, Animal
  • Placenta / cytology
  • Placenta / immunology*
  • Placentation / immunology
  • Pregnancy / immunology*
  • Transplantation Immunology
  • Trophoblasts / cytology
  • Trophoblasts / immunology
  • Uterus / blood supply
  • Uterus / immunology*