Mib1 conditional knockout mice develop an MPD. (A) Cumulative survival of MMTV-Cre;Mib1^+/f (WT; n = 277) and MMTV-Cre;Mib1^f/f (MT; n = 292) mice. (B) Splenomegaly in the 14-week-old MT mice (right) compared with an age-matched wild-type (WT) control (left). (C) Hemograms of 14- to 16-week-old WT (n = 6) and MT (n = 16) mice. Bars indicate the mean. (D-F) Flow cytometric analysis of peripheral blood leukocytes (PBLs) (D,F) and BM cells (E) from 12- to 16-week-old WT (left) and MT (right) mice. Numbers around rectangles indicate the mean plus or minus SD (n = 10). Note that marked eosinophilia with CCR-3⁺ and basophilia with IgE⁺ (F) are evident in the mutant mice. (G and G′) Giemsa staining of blood smears from the WT (G) and MT (G′) peripheral blood. (H,I′) Hematoxylin and eosin staining of the WT (H and I) and MT (H′,I′) spleens (H,H′) and livers (I,I′). (J) Myeloid peroxidase (MPO; in green) and proliferating cell nuclear antigen (PCNA; in red) double immunohistochemistry of the liver (×400) from 15-week-old MMTV-Cre;Mib1^f/f mice. (K) Hematoxylin and eosin staining of MT lung (×200). Scale bars: 50 μm (G, G′, and J); 100 μm (H, H′, I, I′, and K).