Acute GVHD induced after allogeneic BMT using extensive conditioning in mice with or without PPs. (A) TNF^Δ/Δ and TNF^-/- mice develop mesenteric LNs and cecal patches (CPs). TNF^-/- mice develop PPs, but TNF^Δ/Δ mice do not. Not all PPs formed in the TNF^-/- mice are visible. Fresh mouse organs, from representative adult naive animals, were photographed using Nikon Coolpix 2500 digital camera set to macro mode. (B) TNF^Δ/Δ, TNF^-/- mice, or WT mice were used as recipients of allogeneic BM grafts in combination with 3 × 10⁷ spleen cells (SCs) as a source of T cells (n = 9-11 mice/group/experiment). Some groups received BM only to control for non–GVHD-associated changes (n = 3-8 mice/group/experiment). Combined results of 2 independent experiments are shown. No significant differences were observed in mice that received BM and spleen cells. (C) Kinetics of weight loss in one of the 2 independent experiments represented in panel B. (D) TNF^Δ/Δ or WT mice were used as recipients of allogeneic BM grafts in combination with 2.5 or 1.25 × 10⁷ spleen cells (SCs) as a source of T cells (n = 5-8 mice/group). Some groups received BM only to control for non–GVHD-associated changes. Representative results of 2 independent experiments are shown for survival kinetics. No significant differences were observed between experimental groups for either dose of spleen cells.