Organ histology and peripheral blood counts at 3-month time point. (A) The peripheral blood in FLT3/ITD-NHD13 mice contains numerous circulating blasts, and the normal bone marrow is replaced by sheets of blasts. Leukemic infiltrates are present in the spleen, brain, and liver. Bone marrow cytospins in the FLT3/ITD-NHD13 mice show abundant agranular blasts that have a scant to moderate amount of basophilic cytoplasm. Images for the modified Wright-Giemsa stain were acquired at room temperature using a Zeiss Axioskop upright microcope system (Carl Zeiss) with Achroplan 5×/0.16 NA, 10×/0.3 NA, and 40×/0.6 NA objectives and were photographed with an AxioCam camera (Carl Zeiss) and Axiovision Version 4.0 software (Carl Zeiss). (B) Comparison of WBC counts, (C) spleen weights, (D) differential count, (E) and hematocrit. (F) Example of spleen size in 3-month-old littermates representing each genotype.