[Immunology of pregnancy: renewed interest].
The long-standing question of pregnancy immunological paradox has been generating renewed interest. Recent insights have emerged from studies in pregnant mice and humans demonstrating a number of mechanisms that prevent potentially harmful effects of maternal anti-paternal allo-antibodies (complement inhibition, partial deletion of maternal B cells specific of paternal antigens), cytotoxic CD8+ T cells (lack of HLA-A and HLA-B expression on trophoblast, local immunosuppressive molecules, transient tolerance of paternal allo-antigens specific T cells) and uterine NK cells directed against fetal-derived trophoblast cells (limited NK cytotoxic potential, trophoblast resistance to NK killing). Interestingly, it appears that not only decidual NK cell/trophoblast interactions are not harmful for the fetus but are beneficial for the placental vascularization and its subsequent development. A recent report has indeed demonstrated that during pregnancy most of the combinations of uterine KIR (killer cell immunoglobulin-like receptor) NK cell receptors and fetal HLA-C molecules expressed by trophoblast led to normal pregnancies, whereas mothers lacking activating KIR of the AA genotype when the fetus possessed HLA-C of the C2 group were at a greatly increased risk of severe preeclampsia pathology.
Le Bouteiller
Philippe
P
Inserm U563/ Université Paul Sabatier, Hôpital Purpan, Bâtiment A, BP 3028, 31024 Toulouse Cedex 3, France. philippe.le-bouteiller@toulouse.inserm.fr
Tabiasco
Julie
J
D005260:Female; D047109:Fetal Development / Q000276:immunology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008297:Male; D008431:Maternal-Fetal Exchange / Q000276:immunology*; D018448:Models, Immunological; D011247:Pregnancy / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014327:Trophoblasts / Q000276:immunology