Function of the intestinal epithelium and its dysregulation in inflammatory bowel disease

• Published in: Inflammatory bowel diseases Vol. 17; no. 1; pp. 382 - 395
• Main Authors: Henderson, Paul, van Limbergen, Johan E., Schwarze, Jürgen, Wilson, David C.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.01.2011
• Subjects: Antigen presentation; Antigen processing; Antigen-presenting cells; Cell proliferation; Chemokine receptors; Commensals; Differentiation; Effector cells; Enterocytes; Epithelial cells; Epithelium; Humans; Immune response; Immunoglobulin A; Immunoregulation; Inflammatory bowel diseases; Inflammatory Bowel Diseases - physiopathology; Interleukin 22; Intestinal Absorption - physiology; Intestinal Mucosa - physiopathology; Intestine; Lymphocytes; Lymphocytes T; Mucosa; mucosal immunology; Pattern recognition
• ISSN: 1078-0998; 1536-4844; 1536-4844
• DOI: 10.1002/ibd.21379

The intestinal epithelium not only acts as a physical barrier to commensal bacteria and foreign antigens but is also actively involved in antigen processing and immune cell regulation. The inflammatory bowel diseases (IBDs) are characterized by inflammation at this mucosal surface with well‐recognized defects in barrier and secretory function. In addition to this, defects in intraepithelial lymphocytes, chemokine receptors, and pattern recognition receptors promote an abnormal immune response, with increased differentiation of proinflammatory cells and a dysregulated relationship with professional antigen‐presenting cells. This review focuses on recent developments in the structure of the epithelium, including a detailed account of the apical junctional complex in addition to the role of the enterocyte in antigen recognition, uptake, processing, and presentation. Recently described cytokines such as interleukin‐22 and interleukin‐31 are highlighted as is the dysregulation of chemokines and secretory IgA in IBD. Finally, the effect of the intestinal epithelial cell on T effector cell proliferation and differentiation are examined in the context of IBD with particular focus on T regulatory cells and the two‐way interaction between the intestinal epithelial cell and certain immune cell populations. (Inflamm Bowel Dis 2011;)