Leukemia Patients Treated with Cord Blood Face Lower Risk of Complications

Use of blood from the umbilical cord reduces the incidence of a potentially life threatening transplant complication, according to the first study to directly compare such transplants with bone marrow transplants in children with leukemia and other life-threatening diseases.

This cooperative study from the Medical College of Wisconsin's International Bone Marrow Transplant Registry (IBMTR) and the Eurocord-Cord Blood Transplant Group, which is headquartered at Hospital St. Louis in Paris, is reported in the June 22 issue of The New England Journal of Medicine.

Principal investigators for the study included Drs. Elaine Gluckman and Vanderson Rocha from Hospital St. Louis; Mary M. Horowitz, MD, Professor of Medicine and Scientific Director of the IBMTR at the Medical College of Wisconsin; John P. Klein, PhD, Director and Professor of Biostatistics at the Medical College; and Dr. John Wagner, University of Minnesota. Collaborators included investigators from institutions around the world.

The use of donor cord blood from a sibling with the same tissue type resulted in far fewer cases of both chronic and acute graft versus host disease (GVHD) compared with the use of bone marrow from a sibling with the same tissue type. This disorder, which can kill between 20% and 40% of those it affects, arises when the immune cells from the donor attack the recipient whose immune system has been eradicated by high dose chemotherapy and radiation.

"Graft versus host disease is the most important transplant-related complication," said Dr. Horowitz.

Use of cord blood, which is collected from the placenta after delivery, also eliminates the small but real risk of complications to the bone marrow donor, Dr. Horowitz added. Cord blood transplants were first successfully done 11 years ago. Worldwide, there have been 1,300 such transplants -- 200 from related donors; the remainder from unrelated ones. However, up until now there has not been a direct comparison between this method and the traditional method bone marrow transplants.

The researchers compared the records of 113 children who received cord blood transplants from siblings with records from over 2,000 children who received bone marrow transplants from siblings. Fourteen percent of the children who received cord blood developed an acute form of GVHD after the procedure, compared with 24% who received bone marrow transplants.

Of children who lived more than 90 days following the procedures, 6% who received cord blood developed chronic GVHD, while 15% who received bone marrow transplants developed the disorder.

While the occurrence of GVHD is clearly lower among children receiving cord blood instead of bone marrow transplants, the overall death rates are similar.

"The reason survival was the same is that there is a higher risk that the graft won't take since there are not as many cells in the cord blood as in a typical bone marrow transplant. That is the major problem with cord blood transplants," said Dr. Horowitz.

"The results of the study suggest that cord blood transplants should be explored between unrelated donors and recipients," Dr. Horowitz said. "A major advantage in using cord blood is that many bone marrow donors may not be available when needed, and finding a donor can take a lot of time, time the patient may not have. Cord blood, once obtained, is always there."

Cord blood is routinely thrown away after delivery. But a growing number of cord blood banks have developed programs to obtain and store cord blood after obtaining informed consent from the mother.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.