CD4 and Crohn disease: ,33 However, debilitated IEC tight-junctions, as reported in IBDs, facilitate the passage of invading microorganisms that induce a proinflammatory response.34, 35, 36 In particular, HLA expression in IECs is responsible for Crohn’s disease and UC IEC ability to induce CD4+ T cell proliferation and IFNγ secretion.37