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Background High-dose chemotherapy followed by autologous hematopoietic cell transplantation (HCT) is used in many therapeutic protocols for pediatric intra- and extra-cranial solid tumors. HCT can be curative, but is associated with significant toxicity. Procedure Between January 2001 and June 2009, 92 solid tumor patients (age 6 months to 27 years) underwent 94 autologous apheresis procedures at Children's National Medical Center. Out of that group, 71 patients, who underwent 162 autologous HCT, were analyzed for transplant outcomes. Multiple variable modeling was used to identify independent variables related to transplant toxicity outcome measures, such as bacteremia, intensive care admission, and death. Other outcome measures (time to pre-apheresis peripheral blood CD34+ count, product yield, and time to engraftment) were also analyzed. Independent variables included patient-specific variables (age, weight, tumor type, chemotherapy administered, and primary vs. relapsed disease) and harvest or transplant-related variables (total white blood cell and CD34+ cell counts prior to transplant, and quantity of total nucleated cells and CD34+ cells infused during transplant). Results Transplant toxicity was significantly greater in younger patients (P = 0.001) and in neuroblastoma patients (P = 0.003). The time to neutrophil engraftment, controlling for weight, age, and chemotherapy, was positively related to absolute CD34+ cells/kg infused (P = 0.01). The time to CD34+ recovery pre-apheresis was affected by patient diagnosis (P = 0.05). Conclusions Younger patients had increased transplant toxicity, with infants

Purpose: To characterize the relationship between CD34+ collection efficiency and blood volumes processed in pediatric patients undergoing autologous peripheral blood stem cell (PBSC) collection. Methods: Retrospective 8-year (2001–2009) study of pediatric patients (n = 79) with neuroblastoma and central nervous system (CNS) tumors undergoing first day of autologous PBSC harvest using MNC program on the COBE Spectra (Caridian BCT, Lakewood, CO) was performed. Patients undergoing 0 to 2.9 BV (standard volume), 3 to 6 BV (large volume), and greater than 6 BV (ultra large volume) harvests were evaluated for CD34+ collection efficiency, diagnosis (neuroblastoma vs. nonneuroblastoma), disease type (primary vs. relapse), mobilization regimen, granulocyte colony stimulating factor (GCSF) dose, and apheresis complications. Results: CD34+ collection efficiencies (CE) for neuroblastoma patients were 67%, 50%, and 53% for standard (n = 14), large (n = 9), and ultra large (n = 5) volume harvests, respectively. Similarly, patients with nonneuroblastoma diagnoses had CD34+ CE of 63%, 55%, and 65% for low (n = 19), large (n = 27), and ultra large (n = 5) volume harvests, respectively. Weight, granulocyte colony stimulating factor (G-CSF) stimulation, type of mobilization, and apheresis complications (normalized by run time) were similar between the standard, large, and ultra large volume groups in patients with either neuroblastoma or nonneuroblastoma diagnoses. Conclusions: CD34+ collection efficiency in pediatric autologous PBSC collection on the first day of harvest does not decrease with higher numbers of blood volumes processed in patients with either neuroblastoma or nonneuroblastoma primary disease. These results indirectly indicate bone marrow CD34+ cell mobilization occurs with longer apheresis procedures in pediatric patients. J. Clin. Apheresis, 2011. © 2011 Wiley-Liss, Inc.