Preparation of autologous bone marrow grafts for cryopreservation using the AS104 cell separator

We evaluated the AS104 cell separator (Fresenius AG, Bad Homburg, Germany) for ex vivo processing of bone marrow (BM) grafts of 43 patients suffering from germ cell cancer (GCC, n = 22), acute lymphocytic leukemia (ALL, n = 13) and malignant lymphoma (ML, n = 8). Recoveries of total nucleated cells (TNC), mononuclear cells (MNC) and colony-forming units granulocyte-macrophage (CFU-GM) were determined in the BM concentrates prepared for cryopreservation. Hematopoietic reconstitution was analyzed in patients who underwent autologous transplantation following high-dose radio-/chemotherapy (HDRCT). Processing of the BM suspension with a median volume of 1,013 ml (range: 422-1,574) resulted in 156 ml (80-186) within 50-120 min (median: 90). In the BM concentrates, medians of 28.6% TNC (10.6-69.6), 37.9% MNC (22.3-86.4), and 52.4% CFU-GM (20.8-96.4) were recovered. Twenty-six patients underwent HDRCT with reinfusion of autologous BM and were evaluable for engraftment. They received a median of 0.8 x 10 8 MNC/kg (0.3-1.6 x 10 8 ) and 2.2 x 10 4 CFU-GM/kg (0.6-12.8 x 10 4 ) for hematopoietic rescue. Engraftment with neutrophils >500/μl occurred in a median time of 12 days (8-33) in all patients. We conclude that ex vivo processing of autologous BM with median recovery rates of 37.9% for MNC, and 52.4% for CFU-GM, results in a cell population that can rescue patients from HDRCT. The described technique is convenient, time-efficient, and provides reliable results in preparing BM autografts for cryopreservation.