NHD13 mice develop cytopenias, macrocytosis, and myeloid dysplasia, with increased rate of progression to leukemia or death. (A-D) Male and female NHD13 (blue diamond) and wild-type (WT; gray square) littermates were followed with serial complete blood count measurements (WT, n = 2-12; NHD13, n = 3-14). Data from leukemic animals censored at the first time point at which they were noted to be leukemic. Results analyzed for statistical significance using 2-way analysis of variance (ANOVA). P = .0025 for granulocytes; P < .0001 for all other parameters. (E) Normal neutrophil in the peripheral blood of a WT mouse. (×1000 oil immersion). (F) Dysplastic neutrophil in the peripheral blood of representative NHD13 mouse (×1000 oil immersion). (G) Flow cytometric analysis of mononuclear cells in peripheral blood (myeloid, CD11b⁺; lymphoid, CD3e⁺ or B220⁺). (H) Survival curves showing progression to leukemia or death in NHD13 or WT mice (log-rank [Mantel-Cox] test: P = .09). (I) Schematic of transplant setup. Spleen cells (1 x 10⁶) from NHD13 mouse (CD45.2) noted to have high peripheral WBC counts and massive splenomegaly were transplanted to WT CD45.1 recipients. (J) Leukemic donor cells demonstrated engraftment of >90% in recipients at 3 weeks posttransplant. (K) Representative spleens from nontransplanted WT (left) and recipients of NHD13 cells (right) demonstrating splenomegaly consistent with leukemic development at 3 weeks posttransplant. (L) Representative peripheral blood smears from recipients showing blasts consistent with leukemic development at 3 weeks posttransplant.