Rectal tissues from adult patients with shigellosis representing histology (A-C) and LL-37 immunostaining (D-F). (A) SE was completely eroded at the onset of disease (arrow heads). Huge appearance of blood (deep pink) due to hemorrhage was also evident in LP. (B) Partial recovery (arrow) of epithelial erosion (arrow head) and hemorrhage on day 7 following placebo treatments. (C) The epithelial erosion (arrows) and hemorrhage were completely healed by day 7 after treatment with butyrate. (D) Low expression of LL-37 in the SE (arrow heads) on day 1. (E) LL-37 expression in SE was still low (arrow heads) on day 7 after placebo treatment. (F) Treatment with butyrate led to higher and intense expression of LL-37 in SE (arrow heads) on day 7. SE: surface epithelium; LP: lamina propria. In figures A, B, C and F, bars equal to 100 μm. In figures D and E, bars equal to 50 μm.