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% dimeth ylsulfoxide (DMSO) as the sole cryoprotectant without rate-controlled freezing. This method produced high recovery rate for mononucleated ce lls (87%) and elevated trypan blue viability (90%), Autologous periphe ral blood stem cells (PBSCs) and bone marrow cells with plasma and 10% DMSO were frozen and stored in a -80 degrees C mechanical freezer. El even patients with solid and hematological malignancies were transplan ted 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 C FU-GM was 20 x 10(4)/Kg. All patients showed a rapid and sustained eng raftment. 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 ins titutions without rate-controlled freezing facilities.