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New Biotech Partnership Threatens Public Health

Two biotech firms -- Kimeragen Inc. (Newton, PA) and Roslin Bio-Med (Scotland) -- claim that a new "chimeraplasty" or gene modification technology, will make animal-to-human organ transplants (xenotransplants) "safe" by eliminating disease-causing prions and solving the problem of hyperacute rejection.

"These claims are exaggerated and irresponsible," says Campaign for Responsible Transplantation (CRT) spokesperson Alix Fano. "Xenotransplants, by their very nature, are unsafe because of the risk of transferring lethal animal viruses to humans.  That risk will never be eliminated," says Fano.

Xenotransplant proponents say they will breed germ-free and prion-free animals to diminish the risk of transferring animal viruses to humans.  But all mammals produce prion protein (PrP) and the PrP gene is expressed in virtually every organ, making it unlikely that prions can be eliminated. And there are many endogenous viruses of concern.  Pigs - the species being bred for xenotransplants - harbor 50 endogenous viruses (PERVs) per genome. It would be daunting, if not impossible, to eliminate all infectious PERVs from pigs.  In 1996, the Institute of Medicine acknowledged that "it is impossible to have completely pathogen-free animals [as] some potentially infectious agents are passed in the genome and others may be passed transplacentally."  It is also impossible to insure that animals retain the same disease status from day to day.  And there is no way to screen for unknown viruses.

Within the last year, scientists have discovered several new viruses, or strains of viruses, in pigs that were unknown before, including a porcine torovirus, porcine rotavirus (variant 4F), PRRS (porcine reproductive and respiratory syndrome virus), and an H3N2 swine flu virus which is entering humans more often than previously thought and is a descendant of swine flu viruses from over a decade ago.  If transferred to humans through xenotransplants, animal viruses could lie dormant for months or years before being detected.  And as Jonathan Allan, a virologist from the Southwest Foundation for Biomedical Research in San Antonio, Texas has said: "It only takes one transplant to start an epidemic."

French virologist Claude Chastel writes that xenotransplantation will create a "new infectious Chernobyl."  UK-based biologist, Dr. Mae-Wan Ho, author of Genetic Engineering: Dream or Nightmare (1998), writes that "the creation of transgenic animals for xenotransplantation [is] scientifically flawed and morally unjustifiable.  [It carries] inherent hazards in facilitating cross-species exchange and recombination of viral pathogens."

Since 1905, more than 60 humans have died after receiving organs from pigs, goats, dogs, and other animals, often after suffering terrible side-effects, including internal hemorrhaging, related to hyperacute rejection.  But even if xenotransplantation worked perfectly, according to Richard Nicholson, editor of the Bulletin of Medical Ethics, it would only increase life expectancy by 0.02%.  Human-to-human transplant programs in rich countries currently add 0.003% to life expectancy (about one day).

In December, the Washington, DC-based International Center for Technology Assessment will file a legal petition on behalf of CRT, demanding rule-making to prohibit xenotransplants.

"Xenotransplantation is a dangerous, unproven, and expensive medical technology with a terrible track record;  biotech companies seem willing to expose the public to new viruses so they can get a return on their investments.  Public health agencies need to wake up and start working for the public.  We're going to make sure they do," says Fano.