Influence of in vivo macrophage depletion and huPBMC dose on engraftment. Macrophage depletion with clodronate-containing liposomes was performed in group A (left). A cell-dose titration was performed in groups A and B with doses of 5, 10, 20, and 30 × 10⁶ huPBMCs per group. An increase in human CD45⁺ cells (right y-axis) was associated with X-GVHD characterized by weight loss (left y-axis). Symbols ▿, □, and ○ indicate 3 different mice in each dose group. indicates death of the mouse; closed symbols, % human CD45+ cells; and open symbols, weight (as a percentage of the initial weight).