Umbilical-cord blood cell transplantation conditioned with a reduced intensity-regimen is a practical salvage therapy for severe aplastic anemia refractory to immunosuppressive therapy with antithymocyte globulin/ciclosporin.

Immunosuppressive therapy and stem cell transplantation from an HLA-identical donor are the major effective treatments for severe aplastic anemia. However, treatments still need to be developed for patients who do not have a HLA-identical donor and have not shown a clinical response to immunosuppressive therapy. We herein report on 2 patients in whom this problem could be overcome by transplantation of HLA-mismatched umbilical cord blood from unrelated donors. Two Japanese patients with severe aplastic anemia underwent conditioning with fludarabine, cyclophosphamide, and low-dose total-body irradiation and then received transplants of umbilical cord blood. Engraftment of the three lineages occurred without problems. We conclude that umbilical cord blood transplantation with a reduced-intensity conditioning regimen of fludarabine, cyclophosphamide, and total-body irradiation for patients with aplastic anemia is a practical treatment and may be an attractive alternative for patients who does not have an HLA-identical donor and have shown no clinical response to immunosuppressive therapy.