Role of HLA antigens in liver transplantation with special reference to cellular immune reactions

In previous statistical analyses we have demonstrated the importance of the dualistic effect of HLA on liver transplant survival: HLA compatibility decreases cellular rejection but also increases other immunologically mediated, HLA-restricted mechanisms of allograft injury. More recently these results have been confirmed by other researchers, and several studies have shown higher recurrence rates of infectious diseases such as hepatitis B and C and CMV hepatitis for HLA-compatible liver transplants. Although current practice does not consider HLA in liver transplantation, cellular in vitro studies show a significant role of HLA antigens in clinically relevant phenomena. While increasing the amount of infection-related immune damage, HLA compatibility also decreases the alloproliferative response of the recipient to the donor tissue. Further studies must examine whether non-HLA antigens such as tissue-specific antigens and heat-shock-proteins participate in this process, and how target cells can present different peptides such as soluble HLA antigens or viral proteins to the recipient.