pDC hematopoiesis is FL- and IL-7–dependent. UCB CD34⁺ cells were cultured onto OP9-Del1 (▪) or OP9-C (▦) in the presence of FL alone (F), IL-7 alone (7), or both FL and IL-7 (F7). Results show the average ± SD of the number of BDCA-2⁺ CD123⁺ cells produced at day 20 per well from 3 independent experiments.