NFKB1 and irritable bowel syndrome: Although hydrocortisone exerts its effect mainly by acting on mucosal immune cells such as T cells, monocytes, macrophages and dendritic cells [62], we have shown that hydrocortisone also blocks NF-κB activated pro-inflammatory cytokine release from intestinal epithelial cells following infection with IBD mucosa-associated E. coli and is also beneficial in enhancing mucosal barrier function [62,63].