The role of the <i>HLA-G</i> gene and its expression in the genesis of recurrent miscarriage

Abstract

This review summarizes the results of modern foreign and domestic clinical studies that provide information on the importance of the main histocompatibility complex (HLA), in general, and the expression of non-classical HLA-G molecules on trophoblast cells, in particular, in the physiological course of early pregnancy. The HLA-G gene has central functions in the processing and presentation of antigen and inhibits the receptor of NK cells, which leads to a decrease in the immune response at the fetal-maternal interface and provides immune tolerance to the fetus from the maternal body. HLA-G expression is dependent on combinations of transcription factors, miRNAs, and environmental factors. Based on this, more than a hundred studies have been put into clarifying how HLA-G expression influences the development of pregnancy complications, such as recurrent pregnancy losses, in which immunological factors are believed to play a crucial role.