Thawing of cryopreserved hematopoietic progenitor cells from apheresis with a new dry-warming device.

BACKGROUND: Current thawing techniques of cryopreserved progenitor cells are based on the use of a water bath. The aim of this study has been to assess the progenitor cell viability and the time of hematopoietic engraftment after transplantation of cell products thawed with a new dry-thawing device. STUDY DESIGN AND METHODS: In the preclinical phase, two cryobags from the same patient were thawed with the standard technique and with the dry system method in parallel (n=5, Protocol A and Protocol B, respectively). In the clinical phase, cryobags were thawed with the dry system and the time to hematopoietic engraftment after autologous transplantation (n=52) was compared with those of a control group of patients whose progenitor cell products were thawed with the standard technique (n=52). RESULTS: There were no statistical differences in nuclear and CD34+ cell viability, total colony-forming cells, and cloning efficiency after thawing with Protocols A and B. Days to neutrophil (>0.5×10(9) and >1×10(9) /L) and platelet engraftment (>20×10(9) and >50×10(9) /L) were not different between patients transplanted with products thawed with Protocols A and B. CONCLUSION: Progenitor cell viability and function are preserved with this dry-thawing system. The time to hematopoietic engraftment of patients after transplantation is comparable to those infused with progenitor cells thawed with the water bath technique. Thawing cell products without the use of water and in a dry environment might favor the use of this dry method.

Cryopreservation of hematopoietic progenitor cells from apheresis at high cell concentrations does not impair the hematopoietic recovery after transplantation.

BACKGROUND: The high number of nuclear cells (NCs) from hematopoietic progenitor cells-apheresis (HPC-A) requires cryopreservation in large volumes or at high NC concentrations. The effect of NC concentration during cryopreservation has yet to be examined. STUDY DESIGN AND METHODS: In the experimental arm (n = 610, Protocol B), the first HPC-A sample from the patient was cryopreserved in two cryobags and subsequent collections in one cryobag, resulting in high NC concentrations (>100 x 10(6) NCs/mL) in most cases. The effect of NC concentrations at freezing in NC recovery after thawing and engraftment kinetics was analyzed and compared with a group of HPC-A cryopreserved at standard NC concentrations (n = 455, Protocol A). RESULTS: The mean (SD) NC concentration at freezing was 78 (28) x 10(6) per mL (median, 82 x 10(6)/mL; range, 12 x 10(6)-156 x 10(6)/mL) and 183 (108) x 10(6) per mL (median, 156 x 10(6)/mL; range, 16 x 10(6)-678 x 10(6)/mL), for HPC-A cryopreserved according to Protocols A and B, respectively. The NC viabilities of the test vials and HPC-A components after thawing were 88 percent versus 85 percent and 85 percent versus 82 percent, and the cloning efficiency was 49 percent versus 33 percent for Protocols A and B, respectively (p < 0.001). Significant differences were not observed in the recovery of NCs. Days to neutrophil and platelet engraftment were not different between patients transplanted in the standard- (n = 143) or high-cell-concentration group (n = 238). CONCLUSION: The cryopreservation of HPC-A at higher than standard NC concentrations has no adverse impact on hematopoietic reconstitution after transplantation.

Evaluation of an automated cell processing device to reduce the dimethyl sulfoxide from hematopoietic grafts after thawing.

BACKGROUND: The direct transfusion of thawed hematopoietic progenitor cells (HPCs) is associated to transfusion-related side effects that are thought to be dose-dependent on the infused dimethyl sulfoxide (DMSO). Both the effectiveness of a fully automated cell processing device to washing out DMSO and the effects of DMSO elimination over the recovered cells were evaluated. STUDY DESIGN AND METHODS: Twenty cryopre-served peripheral blood HPC bags (HPC apheresis [HPC-A]) were thawed and processed for washing with an automated cell-processing device. Viability, colony-forming units (CFUs), and absolute count of recovered cells were evaluated by flow cytometry immediately after washing as well as at different times after washing and compared with a sample taken just after thawing (control) but maintained at 4 degrees C. DMSO content was measured by high-performance liquid chromatography and the osmolarity with an osmometer. RESULTS: The median recovery of viable total nucleated cells, viable CD34+ cells, and CFU colonies was 89 (range, 74-115), 103 (range, 62-126), and 91 percent (range, 46%-196%), respectively, in the washing group. Recovery of viable CD3+ cells was 97 percent (range, 42%-131%) and CD14+ cells was 82 percent (54%-119%). The percentages of DMSO elimination and osmolarity reduction were 98 (range, 96-99) and 90 percent (range 86%-95%), respectively. Moreover, elimination of the cryoprotectant improved CFU count, viability, and cell recoveries along the time when compared with the control group. CONCLUSION: Washing out DMSO in thawed HPC-A by use of this approach is safe and efficient in terms of recovery and viability of nucleated and progenitor cells. Additionally, the removal degree of DMSO is very high and therefore might ameliorate the transfusion-related side effects.