In January, a terminally ill patient received a pig’s heart. We now know that he was infected with a pig virus

A few months ago, we hoped that we had taken a giant step in the world of xenotransplantation. A terminal patient had managed to live almost three months with a pig’s heart in his chest. Now we have just learned that, for all we know, the failure of the transplant could have been due to a (well-known and, above all, avoidable) risk: a pig virus.

A pig’s heart beating in the chest. In early January, a team from the University of Maryland Medical Center (USA) transplanted a genetically modified pig heart to David Bennett, a 57-year-old American for whom the operation was his last chance. It was a really dangerous operation. In fact, despite the great amount of progress that has been made in this regard, the FDA only allowed it under the rules of “compassionate use” before the imminence of the patient’s death.

During the first months of the year, the news from the University of Maryland was that the pig’s heart was working properly and Bennett seemed to be slowly recovering. However, in early March his condition rapidly worsened and he eventually died. Since then, scientists around the world have been waiting for the first reports of death to further advance the development of xenotransplantation.

The virus. On April 20, Bartley Griffith, surgeon in charge of the transplant, gave a talk at the American Society of Transplantation: what he said left everyone baffled. As he explained, the tests confirmed that David Bennett was infected with a porcine cytomegalovirus. “We are beginning to know why he passed away. maybe [el virus] it was the actor, or it could be the actor, that triggered everything,” Griffit said in the MIT Technology Review.

It hardly matters, really. As Rafael Matesanz, one of the leading Spanish experts in El País, recalled, when pig kidneys were implanted in monkeys in the 1990s, it was discovered that porcine endogenous retroviruses also traveled along with the organs and that precisely these were behind many of the problems caused.

One of the cornerstones of the new xenotransplantation is that we finally had the technology to “clean” those organs and turn them into safe items. What was a porcine cytomegalovirus doing in the patient (whether or not it caused the transplant failure)? That is the question that now has to be resolved in a hurry. Above all, because we know that the technology is safe.

Again, the ghost of Gelsinger. It is not the first time that a major failure that has nothing to do with the technology in question ends up triggering a decades-long break in a line of research. We’ve been looking for the “holy grail” of transplants for a long time, and such a setback may be some of the worst news of the year.

Image | University of Maryland