HP and celiac disease: Zonulin, also known as pre-haptoglobin 2, a human protein analogue to the Vibrio cholerae derived zonula occludens toxin, modulates intestinal permeability and is found increased in intestinal tissues under inflammatory conditions like coeliac disease [44] but also in stool and serum/plasma samples of inflammatory bowel disease (IBD) when compared to healthy controls [45].