Autologous peripheral blood stem cell harvest timing by absolute neutrophil count in children and young adult patients: Single-institute experience.

Background: Myeloablative, high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) improves outcome in some high-risk malignant solid tumors and lymphomas in children and young adults.

Methods: We performed 16 peripheral blood stem cell (PBSC) harvests in 12 children and 2 young adult patients with a high-risk malignant solid tumor or refractory/relapsed Hodgkin's lymphoma from August 2015 to December 2020. In our chemotherapy mobilization protocol, we used an absolute neutrophil count (ANC) of >1 × 10⁹/L following the nadir after chemotherapy as the criterion for undertaking the apheresis.

Results: The median CD34⁺ cell count per kg body weight of the 33 apheresis products was 4.92 × 10⁶ cells/kg (range, 0.34-22.53 × 10⁶ cells/kg). Thirteen of the 14 patients (93%) had successful PBSC collections that met their goals for PBSCT. Three patients did not receive PBSCT due to disease progression prior to transplantation. Prompt engraftment occurred in all the remaining 11 patients with 17 PBSCTs.

Conclusion: Our data suggest that ANC can be helpful as a surrogate parameter in clinical decision-making when the peripheral blood CD34⁺ count is unavailable.