The Pathogenesis of Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBDs) are relapsing, remitting inflammatory diseases of the intestinal tract. Familial aggregation and genome-wide association studies revealed susceptibility variants that point toward a combination of innate immune and adaptive immune dysregulation that in concert with environmental factors, such as our microbiome, can initiate and perpetuate inflammation. Innate immune perturbations include functional abnormalities in the intestinal barrier, endoplasmic reticulum stress, and abnormal recognition of microbes. Adaptive immune changes include dysregulation of cytokines, regulatory T cells, and leukocyte migration. IBD is linked with an abnormal wound-healing response leading to fibrosis. This article summarizes key pathogenic mechanisms in the pathogenesis of IBDs.