Researchers trying to find out what caused the death of the first person to receive a pig heart transplant found that the organ harbored an animal virus, but they still can’t determine if that was related to the patient’s death.
David Bennett Sr.., 57, of Maryland, died in March, two months after the experimental transplant. Doctors at the University of Maryland said Thursday that they had found an unpleasant surprise: viral DNA inside the pig’s heart.
They found no evidence that the virus, called porcine Cytomegalovirus, cause an active infection.
But one of the main concerns with animal-to-human organ transplants is the risk that they could introduce new types of infections to people.
Because some viruses are “latent,” meaning they can be present without causing illness, “could be a stowaway,” Dr. Bartley Griffith, the surgeon who performed Bennett’s transplant, told The Associated Press.
In any case, work is already under way to develop more sophisticated tests to “make sure we don’t miss this type of virusadded Dr. Muhammad Mohiuddin, director of science for the university’s xenotransplantation program.
MIT Technology Review was the first outlet to report on the presence of the animal virus, citing Griffith’s scientific presentation to the American Transplant Society last month.
For decades, doctors have tried unsuccessfully to use animal organs to save human lives. The last resort for Bennett, who was dying and ineligible for a human heart, was to undergo surgery that used a genetically modified pig heart to reduce the risk that his immune system would quickly reject the organ.
The Maryland team said the donor pig was healthy and passed tests required by the US Food and Drug Administration (FDA) to look for infections. The animal was raised on a pathogen-free farm to avoid contagion. revivicorthe company that provided the pig, declined to comment.
Griffith said that his patient, although very ill, was recovering quite well from the transplant when he woke up one day worse, with symptoms similar to those of an infection. Doctors ran several tests to try to understand the cause, giving Bennett a variety of antibiotics, antivirals and a treatment to boost the immune system. But the pig’s heart became inflamed, filled with fluid and eventually stopped working.
“What, if anything, was the virus doing that could have caused the inflammation in his heart?” Griffith asked.
The reaction also does not resemble typical organ rejection, he said, noting that research is ongoing.
Meanwhile, doctors at other medical centers around the country have been experimenting with animal organs in donated human bodies, and are eager to attempt formal studies in living patients soon. It is unknown how the detected swine virus will affect these plans.