The Impact of Graft Composition on Clinical Outcomes in Pediatric Patients Undergoing Unmanipulated HLA-Mismatched/Haploidentical Hematopoietic Stem Cell Transplantation

Objective. In pediatric patients, the association of graft composition with clinical outcomes after unmanipulated haploidentical hematopoietic stem cell transplantation has not been well defined. Therefore, the impact of graft composition on transplant outcomes was evaluated. Methods. We examined the absolute numbers and relative proportions of CD3+, CD4+, CD8+, CD14+, and CD34+ cells contained in allografts of 103 children who underwent unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation (HSCT) without in vitro T cell depletion. Results. Multivariate analysis showed that a high CD34+ cell dose in G-CSF-primed bone marrow and peripheral blood grafts (G-PB) was related to accelerated platelet engraftment (P = 0.004). A higher CD3/CD14 ratio in G-PB (>= 1.30) was associated with grade II-IV acute graft-versus-host disease (GVHD) (HR = 3.552; 95% CI 1.015-12.428, P = 0.047). In addition, only a heavier donor weight (HR = 5.837; 95% CI 1.841-18.513, P = 0.003) and a higher ratio of CD3/CD14 in the total graft (HR = 9.752; 95% CI 1.834-51.865, P = 0.008) were associated with worse overall survival. No aspect of graft composition affected neutrophil engraftment or disease relapse, though occurrence of chronic GVHD and a higher CD3/CD14 ratio in G-PB and total graft may reflect a lower incidence of relapse without statistical significance. Conclusions. The dose of CD34+ cells and the CD3/CD14 ratio in allografts seem to have prognostic value for engraftment and clinical outcomes in pediatric patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation. A lower CD3/CD14 ratio in allografts demonstrated a survival benefit. Pediatr Blood Cancer 2011;57: 135-141. (C) 2011 Wiley-Liss, Inc.