Transgenic mice exhibit enhanced and prolonged response to an inflammatory challenge. Intraepidermal neutrophilic abscesses 6 hours after TPA challenge in transgenic mice (B) compared with low-level dermal inflammatory cell infiltrate in nontransgenic controls (A). Persistent ear swelling 10 days after TPA challenge evidenced by caliper ear thickness in transgenic (DPM) versus control (NTG) ears (C). Histologic resolution of inflammation in nontransgenic ears 10 days after TPA challenge (D). In contrast, transgenic ears (E,F) evidence psoriatic-type changes of increased epidermal thickness, epidermal rete ridge dermal projections, subepidermal edema, and foci of parakeratosis (F). Bar in panel A represents 100 μm.