Morphologic analysis of murine BM and spleen engrafted with CML cells. (A) Histologic section of tibia of NOD/SCID mouse irradiated but not infused with human cells at day 42 (original magnification × 400). (B) Histologic section of tibia of mouse with 28% human cells detectable at day 42. Hypercellular marrow with proliferation of megakaryocytes and eosinophils are shown (original magnification × 400). (C) Histologic section of spleen from control mouse showing monomorphic lymphoid population (original magnification × 400). (D) Histologic section of spleen of mouse with 33% human cells detectable at day 42. Infiltration with megakaryocytes is shown. (E) Cytospin preparation of spleen from control mouse (original magnification × 400). (F) Cytospin preparation of spleen of mouse with 56% human cells detected at day 42 showing prominent magakaryocytes (original magnification × 400).