Production of nucleated cells over 6 weeks of culture from 1,000 CD34⁺, CD34⁺FLT3⁺, and CD34⁺FLT3⁻ cells cultured in 4 HGF + 100 ng/mL FLT3-L. The graph shows results (mean + SEM from triplicate wells) from one representative experiment. At 4 weeks, CD34⁺FLT3⁻ cells produced significantly (P = .05) more cells than either the unfractionated CD34⁺ cells or the CD34⁺FLT3⁺ cells. At both 5 and 6 weeks of culture, significantly greater nucleated cell generation was achieved from CD34⁺FLT3⁻ cells than that achieved by either CD34⁺ or CD34⁺FLT3⁺ cells (P values of .08, .0016, and .03, .005 for weeks 5 and 6, respectively). In contrast, the CD34⁺FLT3⁺ cells were unable to sustain production beyond 4 weeks.