Only pictures of control Thl mice are demonstrated because of the similarity in gut mucosa between WT and Thl mice without DSS. The low magnification pictures (40×) indicate the differences in ulcer sizes between WT+Fe DSS and Thl+Fe DSS. Arrows in 100× magnification pictures indicate the ulcer lesions in DSS-administered mice as determined by the loss of villi and the accumulation of inflammatory immune cells in mucosa and submucosa. The higher magnification (400×) is a representative picture indicating generalized neutrophil accumulation in ulcer (the area with neutrophils are presented with ‘star symbols’ in the 400× picture). Notably, the ulcer in Thl+Fe DSS is larger than WT+Fe DSS despite a similar neutrophil infiltration per area of the ulcer.