Storage of haemopoietic stem cells for autologous bone marrow transplantation

For reinfusing autologous bone marrow cells after high-dose chemotherapy and/or radiotherapy it is necessary that an effective technique for their storage is available. The traditional method uses 10% dimethyl sulphoxide as cryoprotectant, a rate-controlled computerized freezer programmed to cool the cells at a constant rate of 1 degrees C per minute and liquid nitrogen as the storage system. The method is time-consuming, expensive and requires technical expertise. Moreover, it is often associated with varying levels of clinical toxicity following infusion of the preserved cells. Processing the harvest to reduce the initial volume and the mature cells has been shown to be beneficial in reducing the volume of the cryoprotectant and the incidence of toxicity. An alternative, cost-effective method using a cryoprotectant mixture of 5% dimethyl sulphoxide, 6% hydroxyethyl starch and 4% albumin has been found to be effective even when the cells are stored at -80 degrees C without rate-controlled freezing. However, its efficacy needs to be evaluated for extended periods. The current use of purging and cell sorting methods seems to be promising.