Abstract
Ulcerative colitis and Crohn’s disease are chronic inflammatory bowel diseases (IBDs) with a chronic relapsing course. The aetiology of these diseases remains unknown, but in the last decade an increase in experimental models of IBD has led to expansion of our understanding in various aspects of the aetiology and pathogenic mechanisms of IBD. A growing body of evidence coming from these models indicates that an immune response against gut constituents is of critical importance for intestinal inflammation and the subsequent destruction of the mucosa. For this reason, research on IBD has focused intensely on the immune and non-immune cell subsets as well as the soluble mediators involved in normal and dysregulated immune responses. An appreciation of the current knowledge of the pathogenesis of IBD is of paramount importance for the understanding of current, and development of new, treatment modalities.