A significant overlap exists between spondyloarthritis (SpA) and inflammatory bowel disease (IBD), particularly in the IL-23/IL-17 pathway. Shared immunologic mechanisms include aberrant innate immune responses, an excess of Th1/Th17-mediated immunity, and inadequate immune regulation. Many genetic factors associated with IBD are involved in host–pathogen interactions and intestinal barrier function, and the intestinal microbiota do appear to play an important role in disease development. Hence the current hypothesis for IBD pathogenesis is that it stems from a dysregulated immune response to intestinal microbiota in a genetically susceptible host. In SpA, evidence for a role of intestinal microbiota is less abundant, but given the overlap with IBD, it is plausible that gut microbiota are important players in SpA pathogenesis as well. However, there are significant genetic differences between these two conditions, as well as differing responses to biologic therapy.
Role of intestinal microbiota in pathogenesis of inflammatory bowel disease
