Analysis of the leukocyte recovery of recipients transplanted with fresh (empty points) and ex vivo–expanded BM grafts (filled points) containing similar numbers of CFU-GMs. In experiment A, total leukocyte counts (circles) and Gr1⁺ cells (squares) are shown. Experiment B represents the leukocyte values of mice transplanted with fresh BM from normal (○) or 9d 5FU-treated mice (⋄) and with 3d (•), 5d (▾), and 7d (▴) ex vivo–expanded grafts from 9d 5FU-treated mice. Each point represents the mean and standard error corresponding to four recipients individually analyzed 9 days after transplantation.