Inverted spin method for removing RBCs from BM buffy coat products

Hematopoietic Progenitor Cell Apheresis processing

Modern apheresis generally results in a mononuclear cell product that is highly enriched for hematopoietic stem and progenitor cells when performed on patients who have mobilized with myeloid growth factors, CXCR4 antagonists or upon recovery from cytotoxic chemotherapy. The duration of apheresis during the days in which elevated numbers of CD34 positive cells are present in the blood depends upon the efficiency of the apheresis maneuver, the numbers of the CD34 target cell population in the blood, and the weight of the intended transplant recipient. The ability to freeze a hematopoietic progenitor cell (HPC) graft and subsequently thaw it while retaining viability of the hematopoietic stem and progenitor cell population has permitted routine collection of autologous hematopoietic progenitor cell grafts for treatment of patients with cancer using myeloablative doses of chemotherapy and radiation with stem cell support.

Impact of harvest product volume in erythrocyte depletion of allogeneic or autologous bone marrow using COBE spectra

Depletion of bone marrow (BM) from erythrocytes is used to prevent early hemolysis in major ABO incompatible allogeneic hematopoietic cell transplantation (Allo-HCT). This method was also strongly recommended before storing of autologous and even allo-BM for volume reduction in order to prevent early hemolysis and DMSO toxicity after infusion. In our center, erythrocyte depletion of BM harvests has been performed on a continuous flow cell separator, which used a closed system with a high mononuclear cell (MNC) yield and low rate of erythrocyte contamination. According to the protocol of a cellular therapy approach in a cardiovascular collaborative study we have to adopt the process to lower volumes. We aimed to compare our results with standard volume (SV) (historical control) to low volume ED procedures.

PATIENTS AND METHOD

Data has been collected from the last five years. We analyzed 28 cases in the SV group (BM volume >750ml) and 39 cases in the low volume (LV) group. Nineteen of these cases were allogeneic, and 48 were autologous procedures. We used the software COBE PBSC coll vers 5.1 and a standard disposable set (Gambro BCT, Lakewood, USA) for the procedure, and simultaneously, a double bag system with intermediate connectors were used to overcome re-circulation (COBE Spectra Bone Marrow Processing Set, Lakewood USA).

RESULTS

The mean volume reduction was 88% (range, 84.4-93.5%) for SV and 90.8% (range, 87.2-91.3%) for the LV group. We did not find any significant difference for MNC yield, volume reduction rate and CD34+ cell recovery between the SV and LV group. There were no complications experienced with regards to device or technical difficulties during procedures. Acute massive intravascular hemolysis was not observed in allogeneic recipients.

CONCLUSION

ED and volume reduction with COBE spectra produced successful results in standard and low harvest volumes. This process can be successfully applied to lower volumes and comparable results to the SV harvest can be achieved for the ED rate, reduction of volume and recovery of MNCs and CD34+ cells.