In 1988 many scientists were doubtful that a few ounces of umbilical cord blood could help a six-year-old boy with Fanconi anemia, a disease that causes leukemia and bone marrow failure and, untreated, results in early childhood death.

The boy’s mother was pregnant, and the baby she carried was free of the disease and a good tissue match for her brother.

Joanne Kurtzberg, MD, a pediatric hematologist-oncologist at Duke, and a few colleagues worldwide believed there was value in collecting the blood from the baby’s umbilical cord after she was born and transplanting it into her brother to rebuild his immune system.

“People had been researching cord blood and had started to see hints that it was similar to bone marrow but seemed to be even richer in stem cells,” Kurtzberg recalls.

“It looked like it contained enough stem cells to substitute for bone marrow in a transplant. We thought it would work.”

It did work, and over the next five years and 60 or so sibling transplants that followed, another benefit of cord blood became apparent.

A complication known as graft-versus-host disease (GVHD), which occurs when the donor tissue attacks the recipient’s blood and tissues, was much less common in cord blood transplants -- tenfold lower -- than in bone marrow transplants.

Exact Match Not Required

Moreover, the need for transplantation was great, but only 25 to 50 percent of patients could find a perfect tissue match in time to help them.

“We started thinking maybe [cord blood] doesn’t have to completely match,” says Kurtzberg, who now directs the Duke Pediatric Blood and Marrow Transplantation Program.

“Maybe we could use it in people who are unrelated to each other. Think about it: a mom carries a baby who only matches her halfway -- half of the genetic material is from the dad.”

It’s now known that only four of six cord blood “antigens” must match for a transplant to have a reasonable chance of success, while bone marrow requires a greater degree of matching antigens.

As a result, an acceptable match for cord blood may be identified and obtained within a week, whereas matching bone marrow can takes months to locate and obtain -- if it’s available at all.

In 1993 Kurtzberg and the Duke team performed the first cord blood transplant to an unrelated donor. Since then, more than 16,000 unrelated donor transplants have been performed worldwide.

“We’re treating children with leukemia and getting results that are as good as or better than what you would get with bone marrow transplant,” she explains.

“We’re also treating children with genetic diseases specifically within a category of diseases called inborn errors of metabolism. These are children missing one of many enzymes necessary for the development of the brain. We can use this kind of transplant to give them cells that will make that enzyme, preventing brain damage and death. They’re very rare diseases, but they demonstrate how these cells can repair damaged tissue.

“Perhaps someday we’ll know how to do this for Parkinson’s disease, Alzheimer’s, and other more common diseases,” she notes.

“It’s complicated, though! We’re giving these kids super high-dose chemo to wipe out the bone marrow first -- a person who’s 65 can’t tolerate that. We have to find a way to get those cells to grow without such aggressive preparation. We’re learning a lot. Maybe 10, 20 years from now we can use that information to treat these other conditions.”