Successful Retransplantation With Killer Cell Immunoglobulin-like Receptor Ligand-mismatched Cord Blood in Infant Acute Lymphoblastic Leukemia That Relapsed After Transplantation

The prognosis of children with KMT2A -rearranged ( KMT2A -r) acute lymphoblastic leukemia (ALL) remains dismal. This report describes the successful retransplantation of a patient with infant ALL who relapsed both bone marrow and central nervous system. The patient received HLA-matched cord blood transplantation (CBT) and relapsed 18 months later. After achieving the second remission, the patient received a killer cell immunoglobulin-like receptor ligand-mismatched CBT with a reduced-intensity conditioning regimen and has been in remission for 52 months. Thus, killer cell immunoglobulin-like receptor ligand-mismatched CBT with reduced-intensity conditioning might be a treatment option for patients with KMT2A- r ALL who relapsed after transplantation, even with extramedullary relapse.