Morphology of human leukemia cells in the murine peripheral blood and infiltrated tissues.

Murine (A) and original peripheral blood smear (B) from patient 17 showing similar morphology of leukemic blasts. Tissue sections of murine bone marrow (C,D), spleen (E,F), and liver (G,H) were prepared from mice engrafted with cells from patient 19 (C,E,G), and show replacement of the organ architecture with human leukemia cells compared with normal tissue (D,F,H). Arrows indicate foci of leukemic infiltration in the liver (G). Sections were prepared as described in “Patients and methods” and stained with hematoxylin and eosin. The levels of human cell engraftment (as quantified by the proportion of human versus mouse CD45⁺ cells) in the bone marrow, spleen, and liver of the mouse shown in panels C, E, and G were 98.5%, 92.6%, and 95.5%, respectively (data not shown). Original magnification × 1000 for panels A and B, × 200 for panels C through H.