Umbilical Cord Blood Saves Gravely Ill
Providing the strongest argument yet for widespread storage of frozen blood from umbilical cords and placentas, a study of terminally ill people, most of them children, has found that about half were saved by treatment involving a transfusion of so-called cord blood, even though it did not come from a family member.
The results suggest that the cord blood procedure has the potential to save many more lives than bone marrow transplantation because it does not have to match the patient’s blood and tissue types exactly. Hundreds of children with cancer die each year awaiting a donation of bone marrow that matches their own, according to the Leukemia Society of America.
Moreover, the cord blood procedure may be more effective for some patients than bone marrow transplantation, which would have been expected to save only 10% to 20% of the 54 patients studied so far, said Dr. Joanne Kurtzberg, an oncologist at the Duke University Medical Center and the study’s lead author.
“It’s a very important study,” said Dr. Paul McCurdy, director of the blood resources program at the National Heart, Lung and Blood Institute. “This is the first published report of unrelated donor cord blood transplants done at a single institution.”
The findings are “extraordinary,” said Dr. John Wagner, director of bone marrow transplantation at the University of Minnesota School of Medicine. “This should convince everybody in the transplant community that cord blood is here to stay.”
Over the last few years, doctors worldwide have transplanted cord blood into about 200 unrelated children with serious diseases. The results have been very mixed, researchers say.
In March, 18-year-old Michelle Carew, daughter of Baseball Hall-of-Famer Rod Carew, received a much-publicized experimental cord blood transplant as part of her treatment for advanced leukemia at Childrens Hospital of Orange County. She died soon after, possibly because, one expert commented, her treatment was delayed while she waited in vain for a matching bone marrow donor.
Theoretically, such delays could be averted if the findings of the new study, which appears today in the New England Journal of Medicine, are borne out by further research, experts said. The National Institutes of Health has set aside $30 million over five years to fund experimental cord blood banking and research centers, McCurdy said.
Cord blood and bone marrow serve largely the same function in therapy: They are a source of immature “stem” cells, which develop into the white blood cells, killer cells and other vital blood system components that play a role in combating disease.
To treat some leukemia cases, for example, cord blood, like bone marrow, is transfused into a patient only after high-dose chemotherapy or radiation therapy has been used to wipe out the tumor cells. But that process also kills the patient’s own stem cells, which must then be replenished. So regardless of the stem cell source, a patient must first undergo other grueling and hazardous treatments, Kurtzberg explained.
In the new study, Kurtzberg and co-workers present a detailed analysis of the first 25 of the 54 cord blood recipients. Most of the patients, who were from 10 months to 23 years old, had an advanced blood-related cancer such as leukemia or another life-threatening blood disorder. The cord blood came from the New York Blood Center, which has collected and frozen some 6,000 cord blood samples.
The key step was that the researchers partially matched the cord blood type with the patient’s blood type; out of the six different white blood cell structures that play a role in rejecting foreign tissue, the researchers matched no more than three. The fetal stem cells are so undeveloped, the researchers explained, that they are less likely to be recognized as foreign by the recipient’s immune system and rejected.
The scientists found that 12 patients were still alive from seven to 12 months after receiving the cord blood. Meanwhile, 13 had died of “infection, relapse or toxic effects of treatment.” Kurtzberg said that although that success rate may not look high to a layperson, the patients were the sickest of the sick and all of them would have died without treatment.
Most significant, she said, was that the donated stem cells appeared to “take over” in all the surviving recipients with manageable levels of rejection.
All told, including the patients not covered in the New England Journal article, 28 of the 54 patients treated with cord blood since 1993, the last just three weeks ago, are still alive.
In a related article in the same journal, Dr. Pablo Rubinstein of the New York Blood Center reported the successful use of cord blood in the treatment of an unrelated 26-year-old woman with leukemia. It is one of the first detailed reports of the procedure on an adult. So far, most of the subjects have been children, largely because researchers worried that a unit of cord blood--typically two ounces--contained too few stem cells to seed an adult’s full-sized body.
But that may not be such a concern after all. More than eight months after her treatment, the patient is back at work. “The transplantation of cord blood stem cells is feasible in adults,” the researchers write, “despite the relatively low numbers of . . . precursor cells in units of cord blood.”
