Comparison of the cryoprotective solutions based on human albumin vs. autologous plasma: its effect on cell recovery, clonogenic potential of peripheral blood hematopoietic progenitor cells and engraftment after autologous transplantation

Background and objectives: Cryopreservation of peripheral blood hematopoietic progenitor/stem cells (PBPCs) requires the addition of cryoprotectant such as DMSO, often prediluted using human serum albumin solution (HSAS). The goal of our study was to verify whether the HSAS may be replaced by autologous plasma (AP) without negative impact on PBPCs quality and engraftment. AP usage is less expensive and allows performing cell preparation in a 'closed system', and hence to reduce the risk of product contamination.

Materials and methods: Peripheral blood progenitor cells from 18 patients were divided into two aliquots (500 μl) placed in separate vials, each containing 7·5% DMSO prediluted with 5% HSAS or AP. Post-thaw cell recovery and clonogenic potential was evaluated. During clinical part of the study, the impact of both cryoprotective solution on hematopoietic engraftment was evaluated in two cohorts (n = 26) matched for diagnosis, age and the number of transplanted CD34+ cells.

Results: The median recovery of nucleated cells and the number of colony-forming units did not differ between tested cryoprotective mixtures. For AP mixture, neither total protein nor albumin concentration of plasma correlated with cell recovery and clonogenic potential of the PBPCs after cryopreservation. In clinical evaluation, the median time to leucocyte recovery and reconstitution of neutrophils was comparable in both groups: 10 days. We did not observe either significant difference with regard to the time of platelet recovery (median: 15 days for AP vs. 16 for HSAS; P = 0·79).

Conclusions: HSA in cryoprotective mixture may be replaced by AP without negative impact on cell recovery, clonogenic potential or engraftment.