Mucosal Immunology in the Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) includes two major phenotypes, Crohn’s disease and ulcerative colitis, which have different clinical characteristics and immune response profiles. Dysregulation of the intestinal immune response with elevated secretion of proinflammatory cytokines is a hallmark of IBD. In this chapter, we will characterize the cells of the innate and adaptive immunity involved in the pathogenesis of IBD. Innate lymphoid cells as well as dendritic cells, neutrophils, macrophages, B cells and T cells, including Th1 and Th2, Th9 and Th17 cells will be specifically characterized in this scenario. The cross talks and cytokine-mediated regulation of these cells with emphasis on cytokines IL-17, IL-22 and IL-23 will also be emphasized. propria. These antigens can be recognize by TLR or captured by M cells. The exposure of immune cells to the luminal content induces TCD4 + activation, differentiation and inflammatory cytokine release as well as neutrophil recruitment. IgA-opsonized bacteria contributes to the inflammation induced by Fc α RI. Several environmental factors (diet, genetics, lifestyle) can modulate the microbiota composition and the activation of immune cells in the Ulcerative Colitis;