[Unrelated cord blood transplantation in a child with very severe aplastic anemia].

Recently, bone marrow transplantation from an unrelated donor has been recommended as an option for the treatment of very severe aplastic anemia (vSAA) refractory to immunosuppressive therapy (IST) in the absence of a human leukocyte antigen-matched related donor (MRD). For SAA patients with complications such as bacterial infections, prompt transplantation using either a mismatched related donor or cord blood (CB) becomes necessary. However, the former option is associated with graft-versus-host disease, whereas the latter option is associated with a more significant risk of graft failure. We report a patient with vSAA refractory to IST that was repeatedly complicated by bacterial infection. An MRD was unavailable for this patient, so we decided on emergent transplantation and successfully performed CB transplantation (CBT) using a low-dose TBI conditioning regimen. Although it may be necessary to examine more clinical cases in the future, a conditioning regimen such as that involving low-dose TBI may decrease the risk of graft failure, and CBT may become a treatment option for vSAA in the absence of a suitable donor.