Cardiopulmonary xenotransplantation: The past, the present and future prospects

The shortage of donor organs for heart and lung transplantation has stimulated a resurgence of interest in xenotransplantation from other species to humans. Experimental studies in many centres worldwide are using a variety of models in an effort to discover ways of overcoming the major obstacle to successful xenotransplantation, xenograft rejection. The clinical experience with solid organ xenotransplantation began 30 years ago and has been sporadic. An account of the immunological basis of xenograft rejection is presented herein followed by an overview of approaches under study to overcome rejection. We conclude that at present there are insufficient scientific data on which to base clinical cardiopulmonary xenotransplantation.