Under antigen stimulation, IECs have the potential to secrete cytokines, which not only recruit immune cells to the sites of injured mucosa to participate in immune response but also directly induce the overexpression of inflammatory cytokines (tumor necrosis factor-α, interleukin-1 beta, and IL-6), thus leading to the occurrence and aggravation of IBD. This evidence concerns the gene IL1B and inflammatory bowel disease.