Use of different DMSO concentrations for cryopreservation of autologous peripheral blood stem cell grafts does not have any major impact on levels of leukocyte- and platelet-derived soluble mediators

Background aims Infusion of stem cell autografts can be associated with adverse effects. Necrotic normal leukocytes, cytokines or intracellular mediators released from leukocytes and platelets or the cryo-protectant dimethyl sulfoxide (DMSO) may contribute to this. Cryopreservation using 5% instead of 10% DMSO improves CD34(+) cell viability and therefore we investigated whether using less DMSO had favorable outcomes on leukocyte viability and levels of various soluble mediators in the graft supernatant. Methods Peripheral blood autografts were harvested by 20 apheresis procedures in 16 cancer patients, and autograft samples were cryopreserved with 2%, 4%, 5% and 10% DMSO and stored for 5-6 years. After thawing, the viability of neutrophils and lymphocytes was analyzed by flow cytometry and supernatant levels of soluble mediators were determined by enzyme-linked immunosorbent assay (ELISA) analyzes. Results The highest viability of both neutrophils and lymphocytes was detected with 4% and 5% DMSO, whereas decreased viability was observed with 2% and 10% DMSO. Low or undetectable levels of leukocyte-derived intereukin (IL)-6 and tumor necrosis factor (TNF)-alpha and CXCL8, high levels of platelet-derived CCL5 and CXCL4, and high levels of monocyte-derived soluble CD14 were measured independent of the DMSO concentration, except for slightly increased CXCL8 and decreased CXCL4 levels with 2% DMSO. Perforin levels showed a significant inverse correlation with the DMSO concentration. Conclusions The use of different DMSO concentrations affects the viability of normal leukocytes in autologous peripheral blood stem cell grafts, but has only minor effects on supernatant levels of leukocyte- and platelet-derived soluble mediators.