Chapter 11 : Zoonosis as a Risk to the Xenograft Recipient and to Society: Theoretical Issues

Abstract:

Scientists have proffered widely varying opinions on the extent to which xenotransplantation clinical trials threaten to introduce new infections into the human community. Observers at one extreme conclude that the risk of introducing new infections to the human community is too great, and the potential for benefit is too unclear. These observers argue that the only responsible stance is to impose a complete moratorium on clinical xenotransplantation until there is sufficient knowledge to assess these risks. Observers on the other extreme argue that in the absence of data to support these fears, restrictions that slow or halt the progress of xenotransplantation research would unnecessarily impede progress in an area that promises unmeasurable relief to human suffering. Other observers note that both the risks and the benefits associated with clinical xenotransplantation remain theoretical at present. Advocates of this approach argue that these trials can be accompanied by safeguards stringent enough to adequately protect the public. Laboratory-based studies of xenograft survivors will also increase one's ability to quantify xenotransplant-associated risks and thereby expand one's capacity to make science-based assessments of appropriate public policy. The risk that any xenograft recipient may become infected with porcine endogenous retrovirus (PERV) is likely a function of multiple factors associated with the source animal, the xenotransplantation technique, the characteristics of the human recipient, and the level of PERV expression by the transplanted cells. Reviews of historic developments in xenotransplantation coupled with critiques of developing public policy and procedures have furthered efforts at consensus development.