Cryopreservation of hematopoietic progenitor cells with 5-percent dimethyl sulfoxide at -80 degrees C without rate-controlled freezing.

Background: Cryopreservation of hematopoietic cells with the rate-controlled method is used in the majority of centers. In recent years, there has been a trend toward the simplification of the process. Study Design and Methods: A simplified method for cryopreservation was developed with 5-percent dimethyl sulfoxide (DMSO) as the sole cryoprotectant without rate-controlled freezing. Experiments were done with progressive concentrations of DMSO, ranging from 0 to 10 percent. With DMSO concentrations from 5- to 10-percent, the best recovery and viability for hematopoietic progenitor cells were observed. Hematopoietic progenitor cells with plasma and Ei-percent DMSO were frozen and stored in a -80 degrees C mechanical freezer. Ten patients with solid and hematologic malignancies underwent transplantation with autologous hematopoietic progenitor cells. Results: The median number of transfused mononuclear cells and CD34+ cells was 3.70 (3.1-8.2) x 10(8) per kg and 1.70 (0.8-6.5) x 10(6) per kg, respectively. The median number of transfused colony-forming was 12.45 (3.4-55.3) x 10(4) per kg. All patients showed rapid and sustained engraftment. The mean times to reach a neutrophil count of 0.5 x 10(9) per L and a platelet count of 50 x 10(9) per L were 11.50 +/- 1.70 and 13.90 +/- 3.98 days, respectively. All patients are alive and without transfusion requirements in complete remission 2 to 8 months after transplantation. Conclusion: This simplified cryopreservation technique will be useful for institutions without rate-controlled freezing facilities. Moreover, this method diminishes the amount of DMSO infused to patients, as well as its toxicity.