T cell-replete haploidentical hematopoietic stem cell transplantation (TCR-haplo-HSCT) is a potentially curative therapy for pediatric intractable hematological malignancies due to its graft-versus-leukemia efficacy. This single-center cohort study examined the effects of graft composition (T cell type and dose) on pediatric TCR-haplo-HSCT outcomes in 32 children with relapsed/intractable hematological malignancies. Graft T cell composition was classified using flow cytometry. High graft CD8+ T cell doses reduced disease relapse and improved overall survival and event-free survival, but did not increase transplant-related mortality and the incidence of grade III/IV acute graft-versus-host disease. Doses of grafted CD3+, CD4+, and CD34+ T cells did not affect patient outcomes. Children with differing event-free survival times were divided by a graft CD8+ T cell dose cut-off of 2.03 × 108 kg-1. These findings revealed that grafted CD8+ T cells improved the graft-versus-leukemia effect of pediatric TCR-haplo-HSCT without increasing the risk of transplant-related mortality.
Keywords: Children; Graft; Haploidentical hematopoietic stem cell transplantation; Hematologic malignancy; T-lymphocytes.
© 2024. Japanese Society of Hematology.