Scientists are Now Teaching Body to Accept New Organs

The Times Of India - Mumbai, Sunday, 11 November 2018

It was not the most ominous sign of health trouble, just a nosebleed that would not stop. So in February 2017, Michael Schaffer, who is 60 and lives near Pittsburgh, went first to an emergency room, then to a hospital where a doctor finally succeeded in cauterising a tiny cut in his nostril.

Then the doctor told Schaffer something he never expected to hear: “You need a liver transplant.”

Schaffer had no idea his liver was failing. He had never heard of the diagnosis: NASH, for nonalcoholic steatohepatitis, a fatty liver disease not linked to alcoholism or infections. The disease may have no obvious symptoms even as it destroys the organ. That nosebleed was a sign that Schaffer’s liver was not making proteins needed for blood to clot. He was in trouble.

The news was soon followed by another eye-opener: Doctors asked Schaffer to become the first patient in an experiment that would attempt something that transplant surgeons have dreamed of for more than 65 years.

If it worked, he would receive a donated liver without needing to take powerful drugs to prevent the immune system from rejecting it.

Before the discovery of anti-rejection drugs, organ transplants were impossible. The only way to get the body to accept a donated organ is to squelch its immune response. But the drugs are themselves hazardous, increasing the risks of infection, cancer, high cholesterol levels, accelerated heart disease, diabetes and kidney failure.

Within five years of a liver transplant, 25% of patients on average have died. Within 10 years, 35 to 40% have died.

Patients usually know about the drugs’ risks, but the alternative is worse: death.

In 1953, Dr. Peter Medawar and his colleagues in Britain did an experiment with a result so stunning that he shared a Nobel Prize for it. He showed that it was possible to “train” the immune systems of mice so that they would not reject tissue transplanted from other mice.

His method involved injecting newborn or fetal mice with white blood cells from unrelated mice. When the mice were adults, researchers placed skin grafts from the unrelated mice onto the backs of those that had received the blood cells.

The mice accepted the grafts, suggesting that the immune system can be modified. The idea is to isolate regulatory T cells from a patient about to have a liver or kidney transplant. Then scientists attempt to grow them in the lab along with cells from the donor. Then the T cells are infused back to the patient. NYT NEWS SERVICE