FLT3^wt/ITDmice possess enhanced myeloid expansion activity in vivo. (A) In vivo CFU-spleen assay. CFU-S 1, CFU-S 2, and CFU-S 3 indicate primary, secondary and tertiary CFU-spleen assays, respectively. Data are expressed as means (bars) plus or minus SEM (error bars). (B) In vivo competitive repopulation assay. A representative from 3 independent experiments is shown. *P < .05; **P < .001. (C) BM cells from the FLT3^wt/ITD donors demonstrated increased myeloid and reduced lymphoid expansion activity compared with the wild-type competitor cells in the same recipients. Flow cytometry analysis of BM cells from representative recipients in the FLT3^wt/ITD and wild-type groups is shown. Numbers indicate the percentage of cells in each quadrant. wt indicates wild-type.