VALIDATION OF THE USE OF HYDROXYETHYL STARCH (VOLUVEN 6%) TO REMOVE DIMETHYL SULFOXIDE FROM HEMATOPOIETIC STEM CELLS

Abstract

During the process of cryopreservation of hematopoietic stem cells (CTH), the Dimelthyl Sulfoxide (DMSO) is responsible for ensuring a better cell viability and a satisfactory engraftment but, at the time of the graft infusion, it can cause serious adverse events, particularly in young children, in patients with renal dysfunction, cardiac insufficiency, hemodynamic instability, or when the dose of DMSO is equal to or greater than 1g/DMSO/Kg of body weight. An effective way to avoid serious reactions is to remove the DMSO using a washing solution composed by 40% dextran and 4% albumin. We have used this protocol, initially developed by the New York Blood Bank to remove DMSO and improve engraftment of unrelated umbilical cord blood units, since 2011. However, in October, 2023 we were informed with a short notice about the discontinuity of the production of Dextran40 (Laboratório de Insumos Farmacêuticos Ltda ‒ LIFE). Objective: To describe the validation of the DMSO removal of hematopoietic stem cells in a Cellular Processing Laboratory using solution hydroxyethyl starch (HAES)-Voluven® 6% and albumin 4%, comparing the results of removal using Dextran 40 solution with 4% albumin. Methods: We used 22 bags from 7 patients: 16 from leukapheresis of deceased patients and 6 collected as Donor Leukocyte Infusions (DLI) but unused due to the development of Graft-Versus-Host Disease (GVHD). All families gave authorization for the cells to be discarded or used in research. Two similar bags were chosen from the same patient, stem cell source, volume and cellularity for parallel thawing in a 37°C water bath and then adding one of the solutions (Dextran vs. Voluven) in each bag at a 1:1 ratio. A sample was removed for nucleated cell count (CNT) and cell viability. The bags were centrifuged at 2,000 rpm or 805g, 20 minutes, 4°C, with a brake. Using a manual extractor, the supernatant was transferred to another bag and the buffy coats were measured using a 50 mL syringe, resuspended with the same respective thawing solutions and counted again, as well as the supernatant to indicate a possible cell loss. Results: Nucleated cell recoveries using Dextran and Voluven® were similar: median total cells (TNC) 83 (77‒92), lymphocyte 96 (78‒100) and granulocytes 71 (51‒94) using dextran and median total cells (TNC) 88 (75‒100), lymphocyte 100 (83‒100) and granulocytes 71 (58‒100) using Voluven®.There was no cell loss in the supernatant, median TNC 0.06×109 (0‒0.49) and 0.01×109 (0‒0.39), respectively. Conclusion: The DMSO removal using HAES Voluven® 6% solution and albumin 4% was similar to Dextran 40 and, therefore, validated in our service. It is worth to note that the cost is significantly reduced, R$ 3204,99 vs. R$ 2358,03.