Kinetics of human engraftment. Each bar represents the mean percentage of human engraftment in the periodically sampled BM of mice and in the hematopoietic tissues. Human grafts from the cohort of mice described in Figure 1I were analyzed by flow cytometry and depicted as the percentage of nonerythroid CD45⁺ (▦, □) plus erythroid CD45^–CD36⁺ (▨) cells. *P < .05 for day 1 versus day 4.