Donor-derived osteopoietic engraftment after bone marrow cell infusions. (A) Donor osteopoietic cell engraftment, expressed as a percentage of donor bone cells in the metaphysis and epiphysis, when ex vivo–expanded murine MSCs were infused after varying doses of TBI. (B) Donor osteopoietic cell engraftment when NABMC or MSCs were infused after 1125 cGy TBI. All data are mean ± SEM.