Impact of Different DMSO Concentrations in Cryopreservation Mixture on Hematopoietic Recovery After Autologous Transplantation of Hematopoietic Stem Cells.

The procedure of autologous hematopoietic stem cell (HSC) transplantation requires cryopreservation of HSCs. Addition of DMSO (dimethyl sulfoxide) is necessary to secure the viability of such cells, but this cryoprotectant is potentially toxic to stem cell recipient. The concentrations of DMSO in cryopreservation mixture vary strongly between protocols in different transplant centers. Usually, the HSCs are stored in mixtures containing 10% DMSO, but there is no sufficient evidence that this concentration of DMSO is indeed optimal.

The main aim of the study is to evaluate the clinical impact of reduction of DMSO concentration in cryopreservation mixture on engraftment after autologous hematopoietic stem cell transplantation. 150 consecutive patients will be randomly assigned to one of three study arms (50 patients each). HSCs obtained by leukapheresis will be cryopreserved in three concentrations of DMSO: 5%, 7.5%, 10%, respectively. Evaluation of the mixtures will be carried out by monitoring reconstitution of hematopoiesis and the frequency the side effects in patients. The most important aspect of our evaluation will be the speed of neutrophil recovery after transplantation (defined by the first day, when absolute neutrophil count in peripheral blood will be higher than 0.5 G/L). The investigators will also evaluate the toxicity of cell suspension by monitoring the frequency of infusion-related adverse events (like nausea or vomiting) during infusion and 24 hours after transplantation.