Automated Collection of Peripheral Blood Stem Cells with the COBE Spectra for Autotransplantation

Abstract

Abstract Background: A convenient, effective and safe peripheral blood stem cell (PBSC) apheresis procedure is desirable to cope with the increasing requirements for PBSC collections. We performed PBSC harvesting with the novel COBE Spectra Auto PBSC™ system using the default software configuration recommended by the manufacturer. We analyzed collection parameters and clinical efficiency of harvested autografts following high‐dose chemotherapy (HDCT). Patients and Methods: Eighty‐one patients underwent 102 harvests after standard chemotherapy plus filgrastim (5–10 ug/kg/day) to obtain a target of ≥2.5 × 106 CD34+ cells/kg for autologous blood stem cell transplantation. Conventional‐volume leukaphereses (median: 11 leters) were performed using the manufacturer's standard software default regarding inlet flow, harvest/chase volume (3/7 ml) and number of collection cycles. The ratio of ACD‐A to whole blood was initially set at 1:12 (56 collections), later at 1:10 (46 aphereses). Results: With respect to preapheresis counts of 93 (9–876) CD34+ cells/μl, 69 patients (85.2%) achieved ≥2.5 × 106 CD34+ cells/kg by the first apheresis. PBSC products contained medians of 5.0 × 106 (0.7–77.3) CD34+cells/kg and 13.8 × 104 (2.3–105.0) CFU‐GM/kg. A preapheresis count of ≥40 CD34+ cells/μl predicted a single‐apheresis yield of ≥2.5 × 106 CD34+ cells/kg. Apheresis products showed a high mononuclear cell (MNC) purity of ≥89%. The median overal collection efficiency of CD34+ cells (CD34‐CE) was 42.6% (12.2–87.4). The CD34‐CE decreased significantly with increasing numbers of circulating CD34+ cells: 52.5% at CD34+ cells <40/μl versus 41.0% at CD34+ cells ≥40/μl (p ≤ 0.002). Coagulation problems occurred in 3 of 56 procedures at an ACD‐A to whole blood ratio of 1:12, but in no case at 1:10. Patients who underwent HDCT and autologous blood stem cell transplantation (n=40) engrafted in a median time of 9 (8–13) days for absolute neutrophil counts ≥ 0.5 × 103/μl, 10 (8–13) days for WBC > 1.0 × 103/μl and 11 (8–17) days for platelets > 20 × 103/μl. Conclusions: As a result of efficient PBSC mobilization, a single conventional‐volume leukapheresis with the COBE Spectra Auto PBSC system resulted in hematopoietic autografts with ≥ 2.5 × 106 CD34+ cells/kg in 85% of patients. Following the standard PBSC apheresis recommendations of the manufacturer, the Auto PBSC system assures PBSC products with a high MNC purity and a moderate CD34‐CE that declines significantly at increasing levels of circulating CD34+ cells. Leukaphereses performed at an ACD‐A to whole blood ratio of 1:10 should run without coagulation problems.