A simplified method for cryopreservation of hematopoietic stem cells with -80 degrees C mechanical freezer with dimethyl sulfoxide as the sole cryoprotectant.

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 -80 degrees C 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 x 10(8)/Kg and 4.80 x 10(6)/Kg, respectively. The median number of infused post-thawing CFU-GM was 20 x 10(4)/Kg. All patients showed a rapid and sustained engraftment. The mean times to reach a neutrophil count of 0.5 x 10(9)/L and a platelet count of 50 x 10(9)/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.