Virus Detected in Pig Heart Used in Human Transplant

Traces of a virus known to infect pigs were found in a 57-year-old man who survived for 2 months with a heart transplanted from a genetically altered pig, according to the surgeon who performed the procedure.

The presence of the virus's DNA in the patient may have contributed to his sudden deterioration more than a month after the transplant. But there was no evidence that the patient developed an active infection with the virus or that his body had rejected the heart.

‘One of the most pressing objections to animal-to-human transplants using modified animal organs is that it might facilitate the introduction of new pathogens into the human population.’

The patient had been extremely ill before the surgery and had numerous other complications after the transplant. He died on March 8th.

These revelations about the viral traces found in the patient, made last month during an American Society of Transplantation meeting, were first reported in MIT Technology Review.

"we are saddened by the loss of Bennett but that they were not deterred from their goal of using animal organs to save human lives," said Dr. Muhammad Mohiuddin, scientific director of the cardiac xenotransplantation program at the University of Maryland Medical Center.

The pig, which had been genetically modified so that its organs would not trigger rejection by the human immune system, was provided by Revivicor, a regenerative medicine company based in Blacksburg, Virginia.

Virus Hitched a Ride into the Transplanted Heart

University officials said that although the pig had been screened several times for the virus, the tests pick up only active infections, not latent ones in which the virus may hide quietly in the pig's body. (The tests were done on nasal swabs, but the virus was later detected in the pig's spleen.)

The transplant was initially deemed successful. He did not show signs of rejecting the organ, and the pig's heart continued to function for well over a month, passing a critical milestone for transplant patients.

A test first indicated the presence of porcine cytomegalovirus DNA 20 days after the transplant, but at such a low level. About 40 days after the surgery, however, he suddenly became acutely ill, and subsequent tests showed a precipitous rise in viral DNA levels.

Later, doctors treated Bennett with antiviral drugs and intravenous immune globulin), a product made of antibodies, but the new heart filled with fluid, doubled in size, and stopped working, and he was eventually put on a heart-lung machine.

The heart transplant was one of several ground-breaking transplants in recent months that offer hope to the tens of thousands of patients who need new kidneys, hearts, and lungs amid a dire shortage of donated human organs.

But the prospect of unforeseen consequences and particularly the potential introduction of animal pathogens into the human population may dampen enthusiasm for the use of genetically modified organs.

Source: Medindia