Acute lymphoblastic leukemia in childhood treated with non-T-cell depleted bone marrow transplantation from an HLA2 loci (HLA-A and-DRB1)-mismatched mother after early graft failure of cord blood transplantation

Abstract

An 11-year-old boy with acute lymphoblastic leukemia received unrelated cord blood transplantation at the second remission. Because of early graft failure, he was given a second non-T-cell depleted bone marrow transplant from his HLA 2 loci (HLA-A and -DRB1)-mismatched mother 36 days after the first transplantation. Feto-maternal microchimerism was verified before transplantation. The second transplantation was performed with fludarabine/melphalan as a conditioning regimen, and tacrolimus/short-course methotrexate as graft-versus-host disease (GVHD) prophylaxis. Engraftment was prompt with a recovery of neutrophils (>0.5x10⁹/l) by day +10, reticulocytes (>1%) by day +17 and platelets (>50x10⁹/l) by day +18. Mild regimen-related toxicities (grade I gastrointestinal, grade II hepatic) were observed and acute GVHD was grade I (skin: stage 2). No severe complication was noted. At 6 months post-transplantation, he had no chronic GVHD or leukemia relapse. This experience indicates the future feasibility of a back-up non-T-cell depleted transplantation from HLA 2 loci-mismatched and feto-maternal microchimerism-positive mothers in cases with primary graft failure.