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International Journal of Inflammation
Volume 2010 (2010), Article ID 823710, 12 pages
http://dx.doi.org/10.4061/2010/823710
Review Article

Peyer's Patches: The Immune Sensors of the Intestine

1UMR843 INSERM, Université Sorbonne Paris Cité-Diderot, Hôpital Robert Debré, 75019 Paris, France
2Assistance Publique Hôpitaux de Paris, Hôpital Robert Debré, 75019 Paris, France

Received 30 May 2010; Accepted 11 July 2010

Academic Editor: Gerhard Rogler

Copyright © 2010 Camille Jung et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The gut-associated lymphoid tissue (GALT) consists of isolated or aggregated lymphoid follicles forming Peyer's patches (PPs). By their ability to transport luminal antigens and bacteria, PPs can be considered as the immune sensors of the intestine. PPs functions like induction of immune tolerance or defense against pathogens result from the complex interplay between immune cells located in the lymphoid follicles and the follicle-associated epithelium. This crosstalk seems to be regulated by pathogen recognition receptors, especially Nod2. Although TLR exerts a limited role in PP homeotasis, Nod2 regulates the number, size, and T-cell composition of PPs, in response to the gut flora. In turn, CD 4 + T-cells present in the PP are able to modulate the paracellular and transcellular permeabilities. Two human disorders, Crohn's disease and graft-versus-host disease are thought to be driven by an abnormal response toward the commensal flora. They have been associated with NOD2 mutations and PP dysfunction.