Treatment with IFN-γ results in an in vivo selection of WT cells in chimeric mice.Fancc^-/- CD45.2⁺ and WT CD45.1⁺ BM cells were transplanted at a ratio of 3:1 into lethally irradiated WT mice to obtain similar chimerism. Four months after transplantation, the recipients were treated with 400 μg/kg/day of IFN-γ or vehicle control via micro-osmotic pumps. WT CD45.1⁺ cells were measured by fluorescence cytometry up to 4 months following IFN-γ treatment. Individual symbols represent the mean of WT CD45.1⁺ cells (n = 5). Error bars represent SEM. ^*P < .05; ^**P < .0001 comparing chimerism from vehicle-treated versus IFN-γ-treated mice.