Phenotypic response of purified BM CD34⁺CD38^– and CD34⁺CD38⁺ cells to ex vivo culture with HUBECs. (A) A representative experiment showing the phenotypic changes that occurred within FACS-sorted BM CD34⁺CD38^– cells over 7 days of culture with HUBECs + GM36SF. Note that the majority of day-7 HUBEC-cultured cells were either CD34⁺CD38^– or CD34^–CD38^– (N = 8). (B) A representative experiment showing the phenotypic changes that occurred within FACS-sorted BM CD34⁺CD38⁺ cells over 7 days of coculture with HUBECs + GM36SF. At day 7, the majority of the cells are CD34^–CD38^–, but a minor population of CD34^dimCD38^– cells remains. Numbers indicate the percentage of cells in each quadrant.