This is mediated by an arsenal of virulence factors including the adhesin of type I pili, FimH, which can bind to Carcinoembryonic Antigen-related Cell Adhesion Molecules 6 (CEACAM6) receptor.34,35 Interestingly, these receptors are upregulated in the ileal lesions of CD patients, possibly influencing the trajectory of AIEC adaptive evolution.34 This is evident by the enhanced CEACAM6-binding ability of the FimH alleles within the AIEC group relative to their homologues in commensal E. coli. Here, CEACAM6 is linked to Cowden disease.