Higher dose of CD 34+ 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 CD 34+ dose of bone marrow or peripheral blood stem cells ( PBSC s) 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 CD 34+ 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 CD 34+ counts greater than 1.01 × 10 6  kg −1 improved platelet engraftment, improved overall survival, and reduced nonrelapse mortality. In contrast, a higher PBSC CD 34+ dose did not affect the incidence of acute or chronic graft‐versus‐host disease, including engraftment syndrome. These data suggest that a PBSC CD 34+ dose greater than 1.01 × 10 6  kg −1 is optimal for pediatric haploidentical SCT .