No difference in intestinal GVHD in TNF-deficient hosts using extensive conditioning and allogeneic BMT at either early or late time points. (A) Photomicrograph of colonic tissue sections taken from animals after GVHD induction. Moribund mice from the experiment presented in Figure 1C were humanely killed at day 25 after BMT. Colonic tissue was sectioned and stained by hematoxylin and eosin. Representative photomicrographs are depicted. White arrows designate areas of inflammation. Black arrows designate sloughing of epithelium. (B) No difference in GVHD-associated histologic changes observed in the small intestine, large intestine, and liver of TNF^Δ/Δ or WT recipients of allogeneic BM grafts in combination with 3 × 10⁷ spleen cells (SCs) (n = 3/group). Some groups received BM only to control for non–GVHD-associated changes. Mice were assessed 6 days after transplantation. Tissues were assessed for histologic changes in 3 to 4 parameters as described in “Study design” and the sums of these scores are represented for each tissue.