Although it is a relatively new therapy, bone marrow transplantation has become a routine treatment for patients with a variety of genetic disorders and blood diseases. However, for patients who don't have a matching related donor, finding a match can be a long, frustrating, and ultimately unsuccessful process. This is especially true for people from ethnic and racial minorities.
Human umbilical cord blood is a rich source of the stem and progenitor cells that are present in bone marrow, and the National Heart, Lung, and Blood Institute (NHLBI) has made a major investment in studying whether transplantation of cord blood from unrelated donors is a safe and effective therapy for patients with genetic and blood disorders who do not have an HLA-matching donor, especially minorities. Part of that investment included a grant to the New York Blood Center in 1992 to demonstrate that collecting, processing, and long-term storage of umbilical cord blood was feasible.
Although several previous studies have provided evidence that cord blood transplantation can be used for children with some blood cell cancers and genetic disorders, the patient numbers were small, and many questions remained unanswered.
Now, from the New York Blood Center, we have the results of the first 562 transplants with units from their bank, the largest series of unrelated cord blood transplants conducted to date. This study, which appears in the November 26th New England Journal of Medicine, shows clearly that cord blood transplantation is a feasible procedure for patients who do not have a related matching donor. It also confirms earlier findings that the procedure works in children and that it can be successful even if there is not a complete HLA match.
Although the results from this study need to be confirmed and quantified, they clearly advance the field. We now await the results of the national multicenter study of umbilical cord blood transplants from unrelated, newborn donors, which was initiated by the NHLBI two years ago. This study, in which all participating centers will use standardized collection and transplantation protocols, should demonstrate more detailed information about the appropriate dose of cord blood cells for patients of different weights, the effect of patient age on transplant outcome, and the factors that allow mismatched transplants to success with a reduced incidence of acute graft versus host disease.