Flt3^ITD/Runx1^DELand Flt3^ITD/NHD13 have distinct effects on MPP expansion and repopulating activity. (A-D) HSC and MPP numbers in 2 hindlimbs from P14 or 8-week-old adult mice of the indicated genotypes. n = 4 to 13, ∗P < .05, ∗∗P < .01, ∗∗∗P < .001 by one-way ANOVA with Holm-Sidak posthoc test. Error bars reflect the standard deviation. (E-G) Percentage of CD45.2⁺ leukocytes (E), CD11b⁺Gr1⁺ myeloid cells (F), or B220⁺ B cells (G) in recipient mice after the transplantation of 200 sorted MPPs of the indicated genotypes, along with 300 000 CD45.1 competitor cells. Each line tracks donor chimerism for an individual recipient. n = 13 to 14. (H-I) Percentage of recipients with multilineage (lymphoid + myeloid) or myeloid donor cell chimerism >1%, 16 weeks post-transplant for the indicated donor genotypes. P values are shown based on Fisher exact test. ANOVA, analysis of variance.