Anti–IL-21 mAb treatment reduces lethality and weight loss in a xenogeneic model of GVHD. NOD/SCID/γc−/− mice receiving human PBMCs (30 × 106 cells) were treated with anti–IL-21 mAb or isotype control to assess potency for preventing xenogeneic GVHD. (A) Schematic showing the antibody dosing schedule: 200 μg per injection; injections starting on day −1, and 3 times weekly for 6 weeks. (B) Kaplan-Meier survival curves for mice receiving PBMCs only (solid gray line) or PBMCs plus anti–IL-21 mAb (solid black line) or isotype control (dashed black line). (C) Average weight (percentage of initial) for mice surviving on a given day for different groups of mice. *P ≤ .05 for anti–IL-21 from days 14 to 24. n = 5 mice for each group. Two independent experiments were performed with similar results.
