[A Simplified Method for Cryopreservation of Peripheral Blood Stem Cells]

To simplify the traditional method for cryopreservation of peripheral blood stem cells(PBSCs) at -196 degrees C with rate-controlled freezing with 10% dimethyl sulfoxide(DMSO), the simplified method was carried out by freezing the cells to -80 degrees C in low-temperature freezer with the combination of 5% DMSO, 3% hydroxyethyl starch(HES) and 4% human serum albumin(HSA) as cryoprotectant. PBSCs were cryopreserved by different methods. Cell viability and recovery rate of mononuclear cells (MNC), CFU-GM and CD34(+) cells were compared. It was observed that the higher MNC and CFU-GM recovery rates were achieved and without agglutination with the simplified method. It was also found with this simplified method, satisfactory recovery rates of CFU-GM and CD34(+) cells could be obtained when PBSCs were preserved at -80 degrees C as long as 24 months. There was no difference observed in parameters of cryopreserved PBSCs thawed at 37 degrees C and 20 degrees C. After the cells being exposed to 5% DMSO at room temperature for 1 hour, the cell viability decreased from 93.2% to 84.5%, however, the CFU-GM recovery rate was not decreased. It is concluded that the simplified cryopreservation technique is better and simpler than the traditional crypreservation method, will be useful for institutions without rate-controlled freezing facility. Moreover, this method diminishes the amount of DMSO infused into patients, thus decreasing its toxicity.