Gastrointestinal mucosa: IL-6/STAT3 is important for regeneration of intestinal epithelium, maintain barrier integrity, ensure adequate secretion of antimicrobial peptide, support proliferation, and facilitate migration of intraepithelial lymphocytes (99–101). Inhibition of IL-6 signaling (especially trans-activation) suppresses colitis (59, 102). Clinical use of IL-6 inhibition is associated with increased risk of bowel perforation (103). This evidence concerns the gene STAT3 and colitis.