A 57-year-old man from Maryland who survived two months with a heart transplanted from a genetically modified pig has signs of a virus that infects animals, according to the surgeon who performed the first procedure of its kind.
The disclosure supports one of the most pressing objections to animal-to-human transplants, which is that the widespread use of modified animal organs may facilitate the introduction of new pathogens into the human population.
The presence of viral DNA in the patient may indicate an infection that contributed to his sudden deterioration and death on March 8, said Dr. Bartley Griffith, a transplant surgeon at the University of Maryland School of Medicine, during a presentation to the American Society of Transplantation.
Dr. Griffith’s comments were first reported by the MIT Technology Review.
The pig has been genetically modified so that its organs do not cause rejection by the human immune system. The heart was donated to patient David Bennett Sr. of Revivicor, a regenerative medicine company based in Blacksburg, Virginia.
Company officials declined to comment Thursday. University officials said the animal was tested for a virus called porcine cytomegalovirus. But tests only detect active infections, not latent ones, in which the virus can hide quietly in the pig’s body.
Dr. Bartley P. Griffith, left, with Mr. Bennett after the operation in January. Credit … University of Maryland School of Medicine, through EPA, through Shutterstock
Mr Bennett’s transplant was initially considered successful. He showed no signs of organ rejection and the pig’s heart continued to function for more than a month, passing a critical stage for transplant patients.
A test showed the presence of swine CMV in Mr Bennett 20 days after the transplant, but at such a low level that Dr Griffith said he thought it could be a laboratory error. At 45 days after the operation, Mr Bennett became acutely ill and subsequent tests showed a sharp rise in virus levels, Dr Griffith said.
“So we started to think that the virus, which appeared very early on the 20th day as just a flash, started to grow over time and it could be the actor – it could be the actor – the one who started it all.” dr. Griffith told other transplant scientists.
Mr Bennett’s health deteriorated sharply 45 days after the operation, he said.
“On the 45th day, he looked really funky,” said Dr. Griffith. “Something happened. He looked sick. He lost his attention. He wouldn’t talk to us. He was lying in bed, breathing hard and somehow warm.
Heart transplantation has been one of several groundbreaking transplants in recent months that offer hope to tens of thousands of patients in need of new kidneys, hearts and lungs amid acute shortages of donated human organs.
But the prospect of unintended consequences – and in particular the potential spread of animal disease to the human population – may reduce enthusiasm for the use of genetically modified organs.
Many scientists believe that the coronavirus pandemic originated from a virus transmitted from an as yet unidentified animal to humans in China.
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