Ex vivo expansion kinetics of purified CD34⁺ cord blood cells. Cells were cultured in IMDM supplemented with 20% FBS (▩) or FBS plus IL-3, IL-6, and SCF (□). The figure shows the evolution of the cellularity (A) and CFU-GM (B) of cultures established with an initial input of 2.5 × 10⁴cells; the proportion of CFU-GM along the culture (C), and (D) the total composition of fresh (▪) and 6-day incubated samples in the presence of FBS plus IL-3/IL-6/SCF (□). At weekly intervals, cell cultures were diluted with fresh complete medium to reach the initial cell concentration. The figure represents data obtained from one representative experiment.