Recruitment of candidate human stem cells into proliferation. CD34⁺CD38⁻ BM cells were plated at 1 cell per well in SF-medium and supplemented with indicated cytokines at 250 ng/mL, except for IL-3, which was used at 50 ng/mL. #KFM were compared at high (250 ng/mL each) and low (50 ng/mL each) concentrations. The cocktail consisted of the following 6 cytokines: KL, IL-3, IL-6, MGDF, FL, and G-CSF. The total number of clones and colonies (>50 cells) were scored after 10 to 12 days of incubation. 0 = no clones. Results are presented as the means (±SEM) of 4 separate experiments. Paired Student's t-test was performed comparing KFM high with the other cytokine conditions presented. *P < .05; **P < .005.