Higher dose of CD34+ peripheral blood stem cells is associated with better survival after haploidentical stem cell transplantation in pediatric patients

Haploidentical stem cell transplantation (SCT) is increasingly used to treat pediatric patients with malignant or nonmalignant hematological disorders. The CD34+ dose of bone marrow or peripheral blood stem cells (PBSCs) has been shown to be an important determinant of the transplant outcome in adults under various preparative regimens. However, knowledge of the effect of the CD34+ dose in pediatric haploidentical SCT is limited. We analyzed the data of 348 pediatric patients (aged 2‐18 years) with acute or chronic leukemia, myelodysplastic syndrome (MDS), and other hematological disorders that received a transplant between 2002 and 2012. The results of multivariate analysis showed that PBSC CD34+ counts greater than 1.01 × 10⁶ kg^?1 improved platelet engraftment, improved overall survival, and reduced nonrelapse mortality. In contrast, a higher PBSC CD34+ dose did not affect the incidence of acute or chronic graft‐versus‐host disease, including engraftment syndrome. These data suggest that a PBSC CD34+ dose greater than 1.01 × 10⁶ kg^?1 is optimal for pediatric haploidentical SCT.