HLA-G in Transplantation: A Relevant Molecule for Inhibition of Graft Rejection?

Abstract
The human MHC class I molecule HLA‐G has long been known as a molecule selectively expressed by cytotrophoblastic cells. By inhibiting the cytolytic function of decidual NK cells, HLA‐G protects the HLA‐A and ‐B negative semiallogeneic embryonic tissue against the mother's immune system. In the light of this immuno‐suppressive function, the role of HLA‐G in transplantation was investigated. We will review here recently published data on this topic, showing that expression of HLA‐G affects the responsive capacity of the immune system, might directly participate in graft acceptation, and should be taken into account for the monitoring of transplantation patients.