Immuno-tolerogenic functions of HLA-G: Relevance in transplantation and oncology

Over the past few years, the non-classical HLA class I molecule HLA-G has been the center of intense investigations that have led to the description of its particular structural and functional properties. Although located in the HLA class I region of chromosome six, the HLA-G gene may be distinguished from other HLA class I genes by its low polymorphism and alternative splicing that generates seven HLA-G proteins, whose tissue-distribution is restricted to normal fetal and adult tissues that display a tolerogeneic function towards both innate and acquired immune cells. We review here the functions of HLA-G from an immunological stand point, focusing on the recent advances in this field and on their potential impact in human pathologies, such as cancer and organ transplantation.