Improved automated bone marrow processing and enrichment of CD34+ cells by a large-volume apheresis procedure

We investigated the efficacy of bone marrow (bm) processing by a large-volume apheresis procedure using a self constructed sixfold collection bag system for sequential cell collection and analysis for 5 pediatric patients. Quantitation of leukocytes (WBC), CD34+ cells and colony-forming cells (CFU-GM) within the single bags showed a relative time-dependent decrease of all cell fractions during leukapheresis, whereas the relative amount of mononuclear cells (MNC) droped only slightly. At the same time the large volume apheresis (6 x original bm-volume) clearly enhanced the absolute yield of CD34+ cells compared to the standard procedure (3 x bm-volume) for more than 20%. We conclude that large-volume apheresis for bm processing is an efficient technique to improve the yields of progenitor cells.