Analysis of factors for the prediction of the response to xenotransplantation.

Predicting the response to xenotransplantation is difficult, but can be based upon (i) past clinical experience, (ii) opinion surveys and focus groups, (iii) predictable variables, and (iv) the allotransplant experience. Baby Fae, the Pittsburgh baboon liver transplants, and the Jeff Getty baboon marrow transplant have taught us (a) not to underestimate hurdles, (b) to communicate professionally, (c) not to promise too much, (d) that lobbying can be effective, (e) that "being the first" is important, and (f) that the media can be fickle. The Swedish islet cell and the U.S. neural tissue transplants suggest that patients without immediately life-threatening illnesses will accept xenogeneic tissue and that the public/media will not respond negatively when there is little fanfare. Limited opinion surveys/focus groups suggest a degree of reluctance/revulsion that is more common in women, minorities, and the less-educated, and when the likely donor is a subhuman primate. Predictable positive public-response variables include perceptions of (a) adequacy of the scientific base, (b) adherence to globally agreed upon guidelines, (c) legitimacy/competence of regulatory bodies, and (d) adequate infectious risk assessment and management. A likely negative predictor is the role of animal rights activists (more in Europe, less in the U.S. and the developing world). Less predictable is the response of the media and what other societal concerns dominate the news at the time. Cultural concerns will need careful study. Allotransplant experience suggests that informed religious opinion can be accommodating a new technology. Psychological factors will be important and will need professional management.