Absence of IL-15 production by donor-derived BM cells decreases acute GVHD morbidity and mortality. Lethally irradiated wt B6D2F1 mice underwent transplantation with 5 × 106 wt B6 splenic T cells and 1 × 107 TCD BM cells from wt B6 (▪) or IL-15–/– B6 mice (□). Survival was monitored daily (A) and body weights (B) and clinical GVHD scores (C) were collected in a blinded fashion every 3 days after transplantation. Survival data are combined from 2 similar experiments; weight and clinical score data are from 1 of 2 similar experiments. N ≥ 8 mice per group. (D) IL-15–/– B6 donors were pretreated with 10 μg/d rhIL-15 or PBS as a control for 7 days prior to harvest of bone marrow. Survival of allogeneic recipients (N ≥ 12 mice per group) of 5 × 106 wt B6 splenic T cells and 1 × 107 TCD BM cells harvested from rhIL-15–treated IL-15–/– B6 donors (○), PBS-treated IL-15–/– B6 donors (□), or PBS-treated wt B6 donors (▪) was monitored daily after transplantation. All survival times were compared using the logrank test. Mean group weight and clinical GVHD data were compared using a linear mixed effects model as described in “Materials and methods.” Error bars represent standard error of the mean (SEM).
