New procedure allows kidney transplants from incompatible donors

By Sally Robertson, B.Sc.Mar 10 2016

Researchers have found a way to stop patients rejecting kidneys that have come from incompatible donors, potentially slashing the waiting time for thousands of people in desperate need of the procedure.

For the study, which experts are calling “revolutionary,” the researchers used a procedure known as desensitization which involves a “reboot” of the immune system that allows patients to accept kidneys they would otherwise reject. Significantly more patients who underwent the procedure were still alive after eight years than people who stayed on waiting lists or received a kidney from a donor who had died.

The method “has the potential to save many lives,” says Dr Jeffery Berns, kidney specialist and president of the National Kidney Foundation. It could also mean the difference between receiving a transplant and spending a lifetime on dialysis, a draining and difficult process that can essentially take over a person’s life.

Estimates suggest that of the 100,000 individuals in the U.S. who are waiting for a kidney transplant, around 50% have antibodies that will attack a transplanted organ and around 20% are so sensitive that finding a compatible organ is impossible. A number of people with kidney failure simply remove themselves from waiting lists once they realize they will reject an organ and instead resign themselves to a lifetime of dialysis.

In the desensitization process, the patient’s antibodies are filtered out of the blood. The patient then receives an infusion of other antibodies to ensure some protection, while the immune system sets about regenerating its own antibodies. For some reason that is not exactly known, the patient’s newly produced antibodies are less likely to attack the transplanted kidney. Even if the patient’s regenerated antibodies were a concern, drugs can be given to kill any white blood cells that may produce antibodies that would attack the organ.

As reported in the New England Journal of Medicine, Dr Segev (Johns Hopkins University School of Medicine) and team compared 1,025 patients who received a transplant from an incompatible donor with an equal number who stayed on waiting lists or received an organ from a compatible, but deceased donor. After eight years, 76.5% who had an incompatible donor were still alive, compared with 62.9% of those who stayed on waiting lists or received a kidney from a deceased donor and 43.9% who stayed on waiting lists without ever receiving a transplant.

Although the desensitization process is expensive, costing $30,000 in addition to the $100,000 for the transplant itself, scientists argue that this is still cheaper in the long run than dialysis, which costs patients $70,000 every year for the rest of their lives.