Generation of CFU-GM (A) and nucleated cells (B) from 1,000 CD34⁺CD38⁻ BM cells in pre-CFU culture stimulated with either 4 HGF (IL-3, IL-6, G-CSF, and SCF ) or 4 HGF + FLT3L. At each time point, the mean and standard error from three separate experiments with different sources of BM are presented. CD34⁺CD38⁻ cells were cultured in wells of a 24-well plate. At day 14 and at weekly intervals thereafter, the cultures were subjected to 1 in 5 splits and refed with fresh media and HGF.