Human leukemia engraftment of NOD-SCID mice. Sublethally irradiated mice were injected with 1 × 10⁶ unsorted cells (top row) or 5 × 10³ CD34⁺/CD38^--sorted cells (bottom row) from leukemia sample 1 (Tables 1 and 2). After 14 weeks, mice were killed and the bone marrow cells were analyzed for expression of human and murine CD45 (left), and human CD13 and CD33 (right). Total marrow is shown, with no gates applied.