Cord Blood Transplantation in Adults with Acute Leukemia

Abstract

Allogeneic hematopoietic stem cell transplantation (HSCT) with some graft sources such as bone marrow (BM), mobilized peripheral blood (PB) and cord blood (CB) offers the only curative potential for many patients with high risk hematological malignancies, particularly acute leukemia. Although BM from human leukocyte antigen (HLA)–identical related donors within immediate families is a frontline graft source for this treatment, an alternative stem cell source has increasingly provided for patients lacking HLA-identical related donors. Recently, CB has been considered an acceptable alternative to source of stem cells in unrelated allogeneic HSCT for pediatric and adult patients without HLA–identical related or unrelated donors. This review focuses on clinical results of cord blood transplantation (CBT) including factors associated with transplantation outcomes and clinical comparison studies of CBT and other sources of allogeneic HSCT in adults with acute leukemia. Several strategies including a reduced intensity regimen and double CB units from different donors have been developed to overcome the limited cell dose in CBT for adults. Moreover, to reflect the current encouraging reports and potential starategies, the possibility of CB for immune therapy in the setting of allogeneic HSCT is also discussed. More than 50 years ago in 1957, Thomas et al. reported the first experience with allogeneic bone marrow transplantation (BMT) in patients with advanced leukemia (Thomas et al., 1957) and since then allogeneic HSCT has been a curative treatment for patients with both malignant and non-malignant hematologic diseases (Appelbaum, 2007). The initial purpose of infusion of BM was rescue of the BM function against myeloablaitive dose of radiation and/or chemotherapy, which generates killing of leukemia cells. Thereafter, the evidence of a graft-versus-leukemia (GVL) effect, which is mediated by both host histocompatibility antigen-specific T cells, tumor antigen-specific T cells and Natural killer (NK) cells against leukemia cells, confirmed that allogeneic HSCT is also the only form of cancer immune therapy for leukemia refractory to chemotherapy (Jenq & van den Brink, 2010). Although allogeneic HSCT was initially limited to the approximately two-thirds of patients with a suitably HLA–identical related donor, an alternative stem cell source has increasingly provided for patients lacking HLA-identical related donors. After Broxmeyer et al.