Umbilical cord blood transplantation in adult myeloid leukemia

Allogeneic hematopoietic stem cell (HSC) transplantation is a life-saving procedure for hematopoietic malignancies, marrow failure syndromes and hereditary immunodeficiency disorders. However, wide application of this procedure is limited by availability of suitable human leucocyte antigen (HLA)-matched adult donors. Umbilical cord blood (UCB) has been increasingly used as an alternative HSC source for patients lacking matched-HSC donors. The clinical experience of using UCB transplantation to treat pediatric acute leukemias has already shown that higher-level HLA-mismatched UCB can be equally as good as or even better than matched HSC. Recently, large registries and multiple single institutional studies conclusively demonstrated that UCB is an acceptable source of HSCs for adult acute leukemia patients who lack HLA-matched donors. These studies will impact the future clinical allogeneic stem cell transplantation for acute myeloid leukemia (AML), which is the most common acute leukemia in adults. UCB has unique advantages of easy procurement, absence of risk to donors, low risk of transmitting infections, immediate availability, greater tolerance of HLA disparity and lower-than-expected incidence of severe graft-versus-host disease. These features of UCB permit successful transplantation available to almost every patient who needs it. We anticipate that using UCB as a HSC source for allogeneic transplantation for adult AML will increase dramatically over the next 5 years, by expanding the available allogeneic donor pool. Clinical studies are needed with focus on disease-specific UCB transplantation outcomes, including AML, acute lymphoblastic leukemia, and lymphoma.