But despite these problems, Rao does not believe xenotransplantation is impossible. The United Kingdom recommended a moratorium on such operations until the risks are better understood and quantified. In this country, the U.S. Public Health Service and the Institute of Medicine have issued guidelines for such research. But their recommendations do not have the force of law. Dr. Louisa Chapman, the U.S. Centers for Disease Control and Prevention expert in this field, said her agency walks a careful line between overcaution that kills the field of xenotransplants and recklessness that places the public in danger.
Some surgeons are sanguine about the prospects.
Dr. Thomas Starzl, a well-known transplant surgeon at the University of Pittsburgh, touts xenotransplants over artificial organs. Others have a more studied approach. While concerns must be addressed, there may be a future for xenotransplantation, said Dr. Michael DeBakey, a pioneering heart surgeon and chancellor emeritus of Baylor College of Medicine. Even if it doesn't work, it will add to the understanding of the immunological phenomenon. The answer may come from studies outside the norm, Frazier said.