Aspects moléculaires et fonctionnels des cellules NK et relation des NK déciduales avec l’avortement

Abstract

Natural killer (NK) cells play an important role in immunity. They exist in two forms: peripheral NK cells and decidual NK cells. The first type is present in the blood and has a strong cytotoxic capacity, characterized by different activating and inhibitory receptors. The second type, decidual NK cells, are found only in the uterine endometrium, which is transformed into a decidua during pregnancy. Decidual NKs have reduced cytotoxicity, but make an essential contribution to pregnancy, promoting trophoblast and placental development and invasion, improved vascularization and remodeling of spiral arteries, and maintenance of pregnancy. The functional difference between the two NK cell types reflects a pregnancy-specific immune adaptation, the understanding of which is crucial to explain certain gestational complications such as recurrent miscarriage, pre-eclampsia and fetal growth delay.