Collection, cryopreservation and thawing of stem cells for children weighing less than 25 Kg with high-risk neuroblastoma: A single center results in Morocco

ABSTRACT Introduction: An important component of the advances made in neuroblastoma treatment has been the use of peripheral blood stem cells to support high-dose chemotherapy. In this study, we report our experience on a series of small children who have undergone standard and large volume leukaphersis (LVL) procedures, provide an update on a single institution's experience with cryopreservation of autologous peripheral blood stem cells (PBSCs), using 10% dimethyl sulfoxide (DMSO) and applying post-thaw DMSO depletion and analyze a number of variables that may affect viability. Methods: A total of 36 aphereses were performed on 29 children weighing less than 25 kg between July 2016 and October 2019 at the Ibn Sina university hospital. Results: Seven females and twenty-two males, median bodyweight 14 kg (9 - 22). A single apheresis was sufficient to obtain at least 3 × 106/kg body weight (BW) of CD34+ cells in 82.8% of the cases. The LVL was performed in 22 aphereses. A median number of 5.9 × 106/ kg CD34 cells were collected per apheresis. A total of 60 PBSC samples were cryopreserved and 46 samples were infused. The mean cell viability percentage decreased from 94.75 ± 1.14% before freezing to 70.84 ± 8.6% after thawing (p < 0.001). No correlation was found between post-thaw viability and storage time (r = -0.233; p = 0.234) or number of total nucleated cells (r = 0.344; p = 0.073). Conclusion: Leukapheresis is safe and feasible in small pediatric patients if the appropriate measures are used. Cryopreservation poses numerous challenges, especially a decrease in cell viability after thawing.

High Dose Chemotherapy and Autologous Peripheral Blood Stem Cell Transplantation in Pediatric Patients with High-risk Neuroblastoma / 대한수혈학회지

BACKGROUND: High dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) has become standard therapy for high-risk neuroblastoma patients. We performed a retrospective analysis to assess the characteristics of peripheral blood stem cell harvest (PBSCH) and PBSCT and its clinical outcome. METHODS: We reviewed 17 cases of patients with high-risk neuroblastoma that underwent PBSCH and/or high dose chemotherapy followed by PBSCT. RESULTS: Sixteen patients had stage IV neuroblastoma and one patient had a stage III neuroblastoma with MYCN amplification. The median age of the 17 patients was 43 months (range 22~114 months) and the median body weight was 15 kg (range 10~24 kg). After induction chemotherapy using a modified N7 protocol, 34 PBSCHs (1.5 leukapheresis per PBSCH) were performed. A statistically significant correlation was found between the pre-leukapheresis CD34+ cell count and the total number CD34+ cells of the harvested products (P<0.0001). Tyrosine hydroxylase mRNA was not detected by RT-PCR in all of the leukapheresis products. High dose chemotherapy followed by PBSCT was performed in 24 cases. The mean infused CD34+ cell dose was 4.01x106/kg and WBC and platelet engraftment was performed on day 12.0 and 21.5, respectively. Eleven patients died, and six patients are surviving 11 to 68 months after PBSCT (median survival time, 35 months). CONCLUSION: In this single institution study, treatment with high dose chemotherapy and PBSCT was performed successfully for children with high-risk neuroblastoma.