CEACAM6 and Crohn disease: 2001). CEACAM6 also binds a variety of gram‐negative bacteria and mediates internalization and phagocytosis, participating in innate immune defense in the intestine (Chen et al. 1997). Over‐expression of CEACAM6 occurs in Crohn's Disease where it promotes uptake and colonization of small intestine epithelium by adherent, invasive pathogenic E. coli (Barnich et al. 2007).