Cdc42 deletion causes myeloid cell infiltration to various organs and accumulation of myeloid precursors in peripheral blood. (A) Cdc42-deficient mice show myeloid expansion in spleen, liver, lung, and bone marrow, as well as peripheral blood. Histologic analyses of spleen, lung, liver, peripheral blood smears, bone marrow, and bone marrow smear from WT or KO mice were carried out. Sections were stained with hematoxylin and eosin (magnifications: ×600 for spleen, lung, liver, bone marrow, and bone marrow smear; ×200 for blood). Slides were viewed with a Nikon Eclipse 50i microscope (Nikon, Tokyo, Japan) using Plan Apo and Plan Fluor lenses at 20×/0.75 PH, 60×/0.85 PH, and 100×/1.30 oil and Micromount mounting medium (Surgical Medical Instruments, Grayslake, IL). Images were acquired using a Spot camera model Insight 4 (Diagnostic Instruments, Irvine, CA) and were processed with Spot software version 4.0.9 (Diagnostic Instruments). (B) Quantification of differential counts of myeloid precursors in peripheral blood. Myelocytes (> 500) at various stages of differentiation were counted by visual inspection of multiple, randomly selected fields under a microscope. *P < .05; **P < .01; and ***P < .001.