An approach to the control of disease transmission in pig-to-human xenotransplantation

Although several major immunologic hurdles need to be overcome, the pig is currently considered the most likely source animal of cells, tissues and or gans for transplantation into humans. Concerns have been raised with regard to the potential for the transfer of infectious agents with the transplant ed organ to the human recipient. This risk is perceived to be increased as it is likely that the patient will be iatrogenically immunocompromised and the organ-source pig may be genetically engineered in such a way to render its organs particularly susceptible to infection with human viruses. Furthe rmore, the risk may not be restricted to the recipient, but may have conseq uences for the health of others in the community, The identification of por cine endogenous retroviruses and of hitherto unknown viruses have given ris e to the most concern, We document here the agents we believe should be exc luded from the organ-source pigs. We discuss the likelihood of achieving th is aim and outline the potential means by which it may best be achieved.