Autologous Peripheral Blood Progenitor Cells Cryopreserved in 7.5% DMSO Give Faster Hematopoietic Reconstitution Than Cells Cryopreserved in 10% DMSO.
Authors: Mitrus Iwona , Smagur Andrzej , Giebel Sebastian , Gliwinska Joanna , Prokop Magdalena , Chwieduk Agata , Glowala-Kosinska Magdalena , Sadus-Wojciechowska Maria , Holowiecki Jerzy 
Published: October 2019

Abstract
Abstract 3018

Background:
Cryopreservation of autologous peripheral blood progenitor cells (PBPCs) in 10% DMSO is a routine in most transplantation centers. During ASH 2011 Meeting, we presented the results of in vitro research, concerning the optimization of DMSO concentrations for recovery and clonogeneic potential of PBPCs after thawing. We concluded, that reduction of DMSO concentration from 10% to 7.5% may have favorable impact for cell clonogeneicity. Accordingly, we implemented new cryoprotective mixture (7.5% instead of 10% DMSO) into clinical practice. The purpose of this study was to clinically evaluate the changed protocol.

Patients and Methods:
In our department, between Jan 2012-Aug 2012, 56 patients were transplanted with autologous PBPCs cryopreserved in 7.5% DMSO solution (median of age: 57 years, range: 21–66). We compared the data concerning hematopoietic engraftment and the frequency of side effects with historical control – 52 subsequent patients treated with transplantation of PBPSc cells cryopreserved in 10% DMSO (median of age: 57 years, range: 21–66) in a preceding period. Both study groups did not differ significantly with regard to the diagnosis (mostly lymphoproliferative disorders) or disease status at transplantation. As well, the number of transplanted CD34+ cells was comparable: median 6.5′106/kg (range 1.5–24.7) for 7.5% DMSO and 7.5′106/kg (2.1–24.6) for 10% DMSO group, p=0.68. All received G-CSF (filgrastim) starting on day +7 after transplantation.

Results:
The volume of infused DMSO was significantly lower in patients who obtained PBPBc cryopreserved in 7.5% DMSO (median 22.5 ml, range 7.5–45) than 10% DMSO (median: 30 ml, range, 10–160); p=0.02. The time to leukocyte recovery >1′109/L was faster for 7.5% DMSO (median: 11 days, range: 9–12) than in 10% DMSO (median 11 days, range: 10–13), p=0.03. Similarly, reconstitution of neutrophils >0.5′109/L was faster for 7.5% DMSO group: median 11 days (range 9–13 days) vs. 11 days (range 10–13 days), respectively; p = 0.04. We didn't observe significant difference with regard to platelet recovery >50′109/L (median 12 days, range: 0–21 days for 7.5% DMSO vs. median 12.5, range: 0–19 days for 10% DMSO). Hospital stay since HSCT was shorter in case of 7.5% group (median: 14 days, range: 11–21) than 10% group (median: 15 days, range: 13–25); p=0.04. Number of RBC and platelets transfusions as well as transfusion-related complications did not differ between the groups. Adverse events after transplantation were mild and transient, usually grade 1 nausea, and occurred in 20 (38%) patients in 10% DMSO group compared to 24 (43%) in 7.5% DMSO group (p=0.7).

Conclusions:
The analysis of newly implemented cryopreservation protocol suggest that reduction of the DMSO concentration from 10% to 7.5% is associated with faster leukocyte and neutrophil recovery as well as shorter hospital stay. These findings require verification in a prospective, randomized trial.

Disclosures:
No relevant conflicts of interest to declare.