HLA-G molecules in pregnancy and their possible role in assisted reproductive technology

Pregnancy is commonly considered a semi-allograft as half of the fetal genome derives from the father. However in normal pregnancy several tolerance mechanisms have been demonstrated to counteract the maternal immune response. Among these, the expression of HLA-G by invasive cytotrophoblasts has shown to play a role in creating a tolerogenic condition at the feto-maternal interface. The possible role of HLA-G molecules in pregnancy and as a marker for oocyte/embryo selection in assisted reproduction technology is reviewed comparing the contrasting results present in the literature