A Simplified Method for Cryopreservation of Hematopoietic Stem Cells with -80dGC Mechanical Freezer with Dimethyl Sulfoxide as the Sole Cryoprotectant

Abstract

A simplified method for cryopreservation was developed with 10% dimethylsulfoxide (DMSO) as the sole cryoprotectant without rate-controlled freezing. This method produced high recovery rate for mononucleated cells (87%) and elevated trypan blue viability (90%). Autologous peripheral blood stem cells (PBSCs) and bone marrow cells with plasma and 10% DMSO were frozen and stored in a -80dGC mechanical freezer. Eleven patients with solid and hematological malignancies were transplanted with autologous bone marrow or PBSCs. The median number of infused mononuclear cells (MNC) and CD34+ cells were 3.63 × 10⁸/Kg and 4.80 × 10⁶/Kg, respectively. The median number of infused post-thawing CFU-GM was 20 × 104/Kg. All patients showed a rapid and sustained engraftment. The mean times to reach a neutrophil count of 0.5 × 10⁹/L and a platelet count of 50 × 10⁹/L were 11 and 13 days, respectively. All patients are alive and 10 in unmaintained complete remission for 3-9 months after transplantation. These results show the efficacy of this simplified cryopreservation technique that will be useful for institutions without rate-controlled freezing facilities.

Key Words:

• cryopreservation
• cryoprotective agents
• hematopoietic stem cells
• bone marrow transplantation