Histopathology of representative Balb/C animals that underwent transplantation with JAK2WT and JAK2T875N. Panels display hematoxylin and eosin (H&E)-stained sections from bone marrow (BM: A,D), spleen (B,E), and liver (C,F) from Balb/C mice that underwent transplantation with bone marrow cells transduced with either JAK2WT or JAK2T875N. Immunohistochemical staining for von Willebrand factor is shown (G-L) as well as reticulin staining of BM (M,O) and spleen (N,P). Similar features were observed in C57Bl/6 animals, showing high hematocrit levels that underwent transplantation with JAK2T875N. Arrows indicate infiltrated megakaryocytes. Original magnifications are indicated in each panel and inset.