STAT3^−/− mice have altered blood indices, spleen morphology, erythroid dysplasia, anemia, BM changes, and increased myeloproliferation. (A) Automated blood cell counts from 4 STAT3^−/−/WT pairs at 5 weeks of age. Normal ranges for mice are shaded in red. NE indicates neutrophils; BA, basophils; HGB, hemoglobin; HCT, hematocrit; MCV, mean erythrocyte volume; MCH, mean erythrocyte hemoglobin; MCHC, mean erythrocyte hemoglobin content; and RDW, red cell distribution width (an indicator of anemia). (B) Manual counts of all lymphoid and myeloid blood cells from tail clipping blood smears stained with Wright-Giemsa and examined microscopically. At least 200 white cells per smear were counted and data are shown as means ± 1 SD from 6 STAT3^−/−/WT mouse pairs. (C) Photomicrographs of blood smears stained with Wright-Giemsa representing data from 4 STAT3^−/−/WT pairs. Arrows indicate podocytes (target cells). Also shown are hypochromatic erythrocytes, hyperchromatic reticulocytes, and an example of a normal and a hypersegmented neutrophil. *P < .05 by 2-tailed Student t test.