TNF and Granuloma: Based on literature review, individuals with high levels of CEACAM6 and CHI3L1 receptors, which are overexpressed in inflammation, promote AIEC adhesion and invasion to IECs located in the ileum via the type-1 pili's FimH adhesion (44, 47) or colonic IECs via the chitinase ChiA (48), and subsequently, the colonization of AIEC strains promote the secretion of IFN-γ and TNF-α by macrophages, which are likely to stimulate granuloma formation and is a common histological feature of CD (45).