Orphan Drug Allows Kidney Transplant From Relative with Mismatched Blood Type

Newswise, June 17, 2016 — Surgeons at the University of Illinois Hospital & Health Sciences System have — for the first time — used an orphan drug to prevent rejection of a kidney transplanted from a living donor with a mismatched blood type.

Michelle Lee, 47, had been on dialysis for almost six months due to kidney failure from high blood pressure. When her doctors told her she would need a kidney transplant, her three sons immediately stepped up.
“We got worked up, and it looked like I was the best match for my mom,” said Marlon Lee, 22.

Except he wasn’t quite a perfect match.

Marlon has type A blood, while his mother is type O. Without treatment, antibodies in her blood would attack the mismatched organ and cause rejection.

About 15 to 20 percent of people who need a kidney transplant have a living relative who is a perfect tissue match except for the blood group, said Dr. Enrico Benedetti, professor and head of surgery at the UIC College of Medicine.

Many such patients can nevertheless get transplanted, Benedetti said. The recipient must undergo several days of plasma exchanges to remove antibodies from the blood. Usually, this pretreatment, called plasmapheresis, reduces the level of antibodies enough to allow transplantation, though some patients patients must have their spleen — a major producer of antibodies — removed during the surgery.

But for some, plasmapheresis leaves their antibody level still too high. Lee was one such patient.

“This would have caused us to cancel the transplant, except we had experience using a drug called eculizumab, which blocks the blood antibodies from reacting,” Benedetti said.

He and colleagues at UI Health had pioneered the use of eculizimab in three kidney patients with unusually high antibody levels who received cadaver organs.

 One patient had very high antibodies due to numerous blood transfusions; the other two had not responded adequately to plasmapheresis. All three were transplanted successfully with eculizimab.

Lee was given a dose of eculizumab the day before her May 5 transplant, during which surgeons did not remove her spleen. Just five days after transplant, she went home.

Lee will need a few more doses of eculizumab over the next few weeks, Benedetti said, and she will need to take traditional antirejection medications for the rest of her life. But her prognosis is good.
“If we can protect the organ for the first two to three weeks after transplant, we’re mostly out of the woods,” said Benedetti. “The body and organ will acclimate to each other, and antibody interactions aren’t as serious a concern.”

Benedetti said he hopes this technique will allow for more blood-type-incompatible kidney transplants to take place.

“Eculizumab can help prevent rejection among patients that have a living donor and would have otherwise been turned down for the transplant,” he said.