During ex vivo processing of autologous bone marrow (BM) substantial loss of stem and progenitor cells should be avoided to achieve rapid and sustained hematopoietic reconstitution after high-dose radio-/chemotherapy. We processed 25 autologous BM grafts with the Fresenius AS104 cell separator for cryopreservation and we determined recoveries for mononuclear cells (MNC) and colonyforming units granulocyte-macrophage (CFU-GM) in the BM concentrates. To identify cell loss in BM fractions not cryopreserved, we investigated the MNC and CFU-GM content of BM fat and BM blood. MNC and CFU-GM recovery yielded a mean (± SEM) of 42±12 and 54±20% in the BM concentrate. BM fat showed a mean loss of 7±5% for MNC and 4±3% for CFU-GM, BM blood 30 ±12% for MNC and 13±13% for CFU-GM, respectively. CFU-GM recovery was significantly higher in the BM concentrate of patients with hematologic malignancy (FIM) compared with patients suffering from germ cell cancer (GCC): 66 ±21 vs. 43±12% (p<0.02). Seventeen patients (7 GCC, 10 FIM) underwent high- dose chemotherapy or radio-/chemotherapy and were autografted with 0.8 ±0.2x10^8 MNC/kg and 3.7±2.0x10^4 CFU-GM/kg. All patients achieved engraftment with neutrophils > 0.5 x 10^9/l at a mean of 14±6 days. We conclude that; (1) ex vivo processing of autologous BM with a mean recovery of 42% for MNC and 54% for CFU-GM in the BM concentrate can result in a cell population capable of sustained hematopoietic reconstitution, (2) CFU-GM recovery is significantly higher in patients with FIM than in patients with GCC and (3) 37% MNC and 17% CFU-GM represent in fact cell losses recovered from BM fractions not cryopreserved (BM fat, BM blood). Furthermore, it is likely that MNC and CFU-GM not recovered from BM concentrate, BM fat and BM blood are cell losses related to the 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 ‫ס‬ 22), acute lymphocytic leukemia (ALL, n ‫ס‬ 13) and malignant lymphoma (ML, n ‫ס‬ 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 × 10 8 MNC/kg (0.3-1.6 × 10 8 ) and 2.2 × 10 4 CFU-GM/kg (0.6-12.8 × 10 4 ) for hematopoietic rescue. Engraftment with neutrophils >500/l 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. J. Clin.