The immunology of mucosal models of inflammation.

In recent years the status of the inflammatory bowel diseases (IBDs) as canonical autoimmune diseases has risen steadily with the recognition that these diseases are, at their crux, abnormalities in mucosal responses to normally harmless antigens in the mucosal microflora and therefore responses to antigens that by their proximity and persistence are equivalent to self-antigens. This new paradigm is in no small measure traceable to the advent of multiple models of mucosal inflammation whose very existence is indicative of the fact that many types of immune imbalance can lead to loss of tolerance for mucosal antigens and thus inflammation centered in the gastrointestinal tract. We analyze the immunology of the IBDs through the lens of the murine models, first by drawing attention to their common features and then by considering individual models at a level of detail necessary to reveal their individual capacities to provide insight into IBD pathogenesis. What emerges is that murine models of mucosal inflammation have given us a road map that allows us to begin to define the immunology of the IBDs in all its complexity and to find unexpected ways to treat these diseases.