Assessment of extramedullary hematopoiesis and splenomegaly. (A) The reticulated platelets of WT (n = 10), SMS1-KO (n = 5), and SMS2-KO (n = 6) mice were stained with thiazole orange and analyzed by using flow cytometry. Paraffin sections of spleen (B) and bone marrow (C) were stained with hematoxylin and eosin (HE) or with anti-vWF antibody. The vWF-positive MKs in several randomly chosen high-power fields (HPF) were quantified. Scale bars, 50 µm. (D) Representative images of spleens from WT, SMS1-KO, and SMS2-KO mice. The ratios of the spleen to whole body weight were calculated in nine WT, ten SMS1-KO, and seven SMS2-KO mice. Values show the mean ± standard deviation. *P < .05; **P < .005.