Cord blood stem cells may also pose less risk of graft-versus-host disorder, or GVHD, than stem cells from bone marrow. GVHD occurs when the donor's immune cells make antibodies against the host's tissues, resulting in serious complications. In the last ten years, several studies of cord blood transplants have taken place and their results have been published in science and medical journals. In 1996, the New England Journal of Medicine reported the results of 25 consecutive cord blood transplantations from August 1993 to November 1995 by Dr. Joanne Kurtzberg at Duke University. After bone marrow searches were unsuccessful for 17 patients, cord blood was collected from unrelated donors at the New York Blood Center. Nineteen patients had malignant diseases and four had nonmalignant conditions. The patients' average age was seven years and the average weight was 19.4 kilograms. Twenty cord blood units were slightly HLA-mismatched and one was HLA-identical. The HLA, or Human Leukocyte Antigen, induces the formation of antibodies because it is recognized by the immune system as a threat. Engraftment was successful in 23 of 25 patients, and only two patients had severe graft-versus-host disease. In contrast, bone marrow transplants in children have a 30 percent incidence of graft-versus-host-disease. Seven of the patients with malignant disease and 6 with nonmalignant conditions were alive one year after transplantation. The report concluded that "HLA-mismatched cord blood is an alternative source of stem cells for transplantation in children."" In another study by Dr. John Wagner at the University of Minnesota Hospital, 13 patients with malignant leukemia diseases and five with nonmalignant conditions received cord blood transplants between July 1994 and December 1995. The average age of these patients was 2.7 years and the average weight was 15.4 kilograms. Seven patients received HLA-matched blood and 11 received varying degrees of HLA-mismatched grafts.
