The influence of cell concentration at cryopreservation on neutrophil engraftment after autologous peripheral blood stem cell transplantation

Abstract

BackgroundPeripheral blood stem cell concentrations are traditionally adjusted to 20–40 × 106 leukocytes/mL prior to freezing. This low cell concentration at cryopreservation implies larger volumes with more dimethyl sulfoxide being used, and higher cost and toxicity at the time of transplant. Higher cell concentrations have been reported but this is not widely accepted. Moreover, the influence of cell concentration on engraftment has not been well documented. Therefore, this study retrospectively analyzed the influence of peripheral blood stem cell concentration at freezing on engraftment after autologous hematopoietic stem cell transplantation.MethodLeukapheresis products were plasma-depleted and cryopreserved with 5% dimethyl sulfoxide, 6% hydroxyethylamide solution and 4% albumin in a −80 °C freezer. Individual patient data from hospital records were reviewed.ResultsFifty consecutive patients with oncological diseases underwent 88 leukaphereses. Median age was six years (range: 1–32 years) and median weight was 19 kg (range: 8–94 kg). Median leukocyte concentration was 109 × 106/mL at collection and 359 × 106 (range: 58–676 × 106) at freezing with 78% viability (range: 53–95%); leukocyte recovery after thawing was 95% (range: 70–100%). In multivariate analysis, cell concentration (p-value = 0.001) had a negative impact on engraftment. Patients infused with bags frozen with <200 × 106 leukocytes/mL engrafted after a median of nine days (range: 8–12 days), 200–400 × 106 leukocytes/mL after 11 days (range: 9–20 days); 400–600 × 106 leukocytes/mL after 12 days (range: 8–19 days) and with cell concentrations >600 × 106 leukocytes/mL, engraftment was after 14 days (range: 13–22 days).ConclusionIn patients with adequate CD34 cell collections, total leukocyte concentrations of 282 × 106/mL, freezing with 5% dimethyl sulfoxide and 6% hydroxyethylamide solution without a controlled-rate freezer, and storing cells at −80 °C yielded excellent engraftment. Further increases in cell concentration may delay engraftment, without affecting safety.

Coronavirus disease 2019 pandemic and allogeneic hematopoietic stem cell transplantation: a single center reappraisal

“…One of the main concern related to cryopreservation is represented by the loss of viable cells due to unit processing or during the storage [ 16 , 17 ]. This risk may be exacerbated if products are cryopreserved at cell concentration greater than 2 × 10 8 /ml, or if they contain a large amount of granulocytes [18] , [19] , [20] . In this study, we confirmed that part of viable CD34 + cells was lost with cryopreservation.…”

Effect of high nucleated cell concentration on product viability and hematopoietic recovery in autologous transplantation

“…On the other hand, Felix et al reported that progressively higher cell concentrations (ranges from less than 2 × 10 8 WBC/mL to greater than 6 × 10 8 WBC/mL) was associated with incrementally longer days to initial ANC recovery in pediatric patients (p values of between‐group comparisons were not reported). Our study of adult patients, in contrast, did not find between group differences in initial ANC recovery, even when the very high NC group (≥5 × 10 8 NC/mL) was compared to the low NC group.…”

“…1 In spite of the first report by Rowley, the optimal NC concentration of cryopreserved HPC(A) products has remained controversial as the majority of the recently published literature suggests that this optimal concentration should be less than 3 × 10 8 NC/mL. [2][3][4][5][6][7][8] Administering lower total product volumes with high NC concentrations, however, may have the potential benefit of decreasing volume-and dimethyl sulfoxide (DMSO)-related patient complications, while maximizing the laboratoryʼs liquid nitrogen (LN2) freezer storage capacity. Our study is a retrospective investigation of the effect of HPC(A) products with cell concentrations greater than 3 × 10 8 NC/mL on clinical and product outcomes in patients undergoing autologous PBSC transplantation.…”

“…Twenty‐five years have passed since the first publication by Rowley suggesting that cryopreserving PBSC products at relatively high cell concentrations of 3.8 × 10 8 nucleated cells (NC) per mL did not show detrimental effects on the kinetics of engraftment . In spite of the first report by Rowley, the optimal NC concentration of cryopreserved HPC(A) products has remained controversial as the majority of the recently published literature suggests that this optimal concentration should be less than 3 × 10 8 NC/mL . Administering lower total product volumes with high NC concentrations, however, may have the potential benefit of decreasing volume‐ and dimethyl sulfoxide (DMSO)‐related patient complications, while maximizing the laboratoryʼs liquid nitrogen (LN2) freezer storage capacity.…”

Cryopreservation of Hematopoietic Stem Cells: Emerging Assays, Cryoprotectant Agents, and Technology to Improve Outcomes

“…Despite these factors, the influence of cell concentration on cryopreservation outcome is not well studied [65]. Two studies have demonstrated that cryopreservation of PBSCs at a concentration of 2 × 10 8 cells/mL still yielded high recovery of viable cells [66] and excellent engraftment after autol­ogous PBSC transplantation [65]. An earlier study even indicated a cell concentration of 3.7 ± 1.9 × 10 8 for cryopreservation of PBSCs did not result in loss of engraftment potential [67].…”