Allogeneic hematopoietic stem cell transplantation for lymphoma: stem cell source, donor, and HLA matching
Hematopoietic stem cell transplantation (HSCT) is an integral part of the treatment armament of lymphoma. Historically, autologous transplantation has been the preferred modality for the treatment of relapsed or refractory lymphoma. Recently, the number of allogeneic transplants for lymphoma has grown dramatically. The proper role of allogeneic HSCT for treatment of lymphoma continues to be defined. Stem cell source, donor choice, and the degree of human leukocyte antigen (HLA) matching strongly influence a variety of outcome measures including hematologic recovery, graft-versus-host disease, and survival. Stem cells can be procured from bone marrow, peripheral blood, and umbilical cord blood. Mobilized peripheral blood stem cells collected from an HLA-identical related or unrelated donor represents the most widely used source of stem cells for transplants. The outcome of transplantation using stem cells from mismatched umbilical cord blood or haploidentical family members now appears to be comparable to that of HLA-matched unrelated donor transplantation. This has vastly improved the accessibility of HSCT for patients with lymphoma. However, with the advent of immunotherapy and targeted therapies, the risk versus benefit consideration for allogeneic HSCT will need to be continuously reassessed.
