A Maryland man who died of no clear cause two months after receiving the first ever transplant of a genetically modified pig heart may have been the victim of a pig virus linked to transplant failure, the patient’s doctor discovered, according to MIT Technology Review.
David Bennett Sr., who had end-stage heart disease, received the interspecies transplant January 7 at Baltimore’s University of Maryland Medical Center, and he initially seemed to respond well before unexpectedly deteriorating and dying March 8.
Dr. Bartley Griffith, Bennett’s transplant surgeon, said at an American Society of Transplantation webinar last month the heart was infected with porcine cytomegalovirus, which may have caused Bennett’s death, MIT Technology Review reported Wednesday.
The pig was raised by biotech company Revivicor, which altered the pig’s genome to reduce the risk of Bennett’s body rejecting the heart and to prevent excess tissue growth following the transplant.
If the virus caused Bennett’s death, it represents an obstacle that can probably be overcome in future operations, Griffith reportedly said during the webinar.
Revivicor declined to comment on the virus to MIT Technology Review, and did not immediately respond to a request for comment from Forbes.
The possibility that a pig virus could adapt to infect humans as a result of a transplant has worried researchers, who hope interspecies transplants could eventually help solve a dire shortage of human organ donors. Because of the risk of dangerous cross-species disease transmission, animal transplant recipients and their personal contacts—including pets—should be checked on at regular intervals, a group of transplant researchers said in a 2013 paper published by the National Center for Biotechnology Information. However, porcine cytomegalovirus is not thought to be able to infect humans, Massachusetts General Hospital transplant infection specialist Jay Fishman told MIT Technology Review. Baboons have been used to test techniques for pig-to-human transplants, and have shown the danger posed by porcine cytomegalovirus. A 2015 study published by the NCBI found pig-to-baboon kidney grafts failed nearly four times faster when the virus was present, and a 2020 Nature study found pig-to-baboon heart transplants with the virus failed quickly while virus-free transplants could last more than six months. The authors of the Nature study said infected hearts showed extremely high levels of the virus, possibly due to the intentional inhibition of the baboon’s immune system during transplantation or due to the absence of the pig’s immune system, which might have been better suited to suppress a pig-specific virus. A human who received a porcine cytomegalovirus-infected heart would very likely suffer the same reduced survival time, the researchers said.
“Man Who Received Pig Heart In Medical First Dies 2 Months After Transplant” (Forbes)