Researchers trying to find out what killed the first person to receive a heart transplant from a pig have found that the organ contains an animal virus, but cannot yet say whether it played a role in the person’s death.
A Maryland man, 57-year-old David Bennett Sr., died in March, two months after the groundbreaking experimental transplant. Doctors at the University of Maryland said on Thursday that they had found an unwanted surprise – viral DNA in a pig’s heart. They found no evidence that this bug, called porcine cytomegalovirus, was causing an active infection.
But the main concern about animal-to-human transplants is the risk that it could lead to new types of human infections.
Because some viruses are “latent,” meaning they lurk without causing disease, “it could be a hitchhiker,” Dr. Bartley Griffith, the surgeon who performed Bennett’s transplant, told the Associated Press.
However, more sophisticated testing is underway to “make sure we don’t miss these types of viruses,” added Dr. Muhammad Mohiudin, the university’s scientific director of the xenotransplant program.
The animal virus was first reported by the MIT Technology Review, citing a scientific presentation Griffith gave to the American Transplant Society last month.
For decades, doctors have tried unsuccessfully to use animal organs to save lives. Bennett, who was dying and not eligible for a human heart transplant, underwent a final operation using a genetically modified pig’s heart to reduce the risk of his immune system quickly rejecting such a foreign organ.
The Maryland team said the donor pig was healthy, passed the testing required by the Food and Drug Administration to check for infections, and was kept in a facility designed to prevent the spread of animal infections. Revivicor, the company that provided the animal, declined to comment.
Griffith said that his patient, although very ill, was recovering quite well from the transplant when he woke up one morning with symptoms similar to an infection. Doctors conducted numerous tests to try to understand the cause, and gave Bennett various antibiotics, antiviral drugs, and immune-boosting treatments. But the pig’s heart swelled, filled with fluid, and eventually stopped functioning.
What did the virus do if there was anything that could cause swelling in his heart? Griffith asked. “Honestly, we don’t know.”
The reaction also did not appear to be a typical organ rejection, he said, noting that the investigation was still ongoing.
Meanwhile, doctors at other medical centers in the country are experimenting with animal organs in donated human bodies and are working to make official studies of living patients soon. It is unclear how the swine virus will affect these plans.
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The Associated Press’s Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Scientific Education. AP is solely responsible for all content.
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