Evaluation of a Hydroxyethylstarch Solution for Dimethyl Sulfoxide Removal from Mobilized Peripheral Blood using an Automated System

Abstract

Background and objectives: This study evaluates the efficacy of synthetic colloid hydroxyethyl starch for use as a washing solution to remove DMSO from hematopoietic stem cells cryopreserved grafts in comparison to a crystalloid based solution. 

Materials and methods: We evaluated samples of cryopreserved mobilized peripheral blood (MPB) from 6 (six) patients that had not been used for transplant. For comparison, we used two equal bags of the same collection procedure, allowing the analysis of two different solutions simultaneously. Washing solutions were used: a crystalloid solution (solution 1, sodium chloride 0.9%) and a colloidal solution (solution 2, hydroxyethyl starch 6%), both added with human albumin 2.5%. The washes were performed using the SEPAX2™ (Biosafe) system automated methodology, using the CS-600.1 kit (Biosafe), according to the washing protocol established by the manufacturer. 

Results: The washing solution containing HES showed a statistically significant increase in the recovery of CNT and CD34+/CD45+ cells (p = 0.0313, both), in addition to a greater number of CFU-GM colonies (without statistical significance) when compared to the 0.9% sodium chloride solution. Furthermore, the wash solution containing HES also prevented significant clumping, contrary to what was observed in the wash with 0.9% sodium chloride solution. 

Conclusion: This work shows that the colloidal washing solution containing hydroxyethyl starch is a good option for DMSO removal procedures in samples of cryopreserved mobilized peripheral blood, maintaining the CD34⁺ cells viability and functionality and reducing the cell clumping.