Chronic bowel inflammation and inflammatory joint disease: Pathophysiology

Bowel inflammation is closely linked to chronic joint inflammation. Research reported in the 1980s demonstrated bowel inflammation with gross and microscopic pathological features identical to those of Crohn's disease in over 60% of patients with spondyloarthritis (SpA). Numerous prospective studies have evidenced joint involvement in patients with chronic inflammatory bowel disease (IBD) and bowel inflammation in patients with SpA. Nevertheless, the interactions of joint disease and chronic bowel inflammation remain incompletely elucidated. Two main hypotheses have been suggested to explain potential links between inflammation of the mucosal immune system and peripheral arthritis: one identifies gut bacteria as potentially implicated in the development of joint inflammation and the other involves the recruitment of gut lymphocytes or activated macrophages to the joints. Pathophysiological investigations have established that HLA-B27 is a pivotal pathogenic factor. Here, we review current data on links between chronic bowel inflammation and inflammatory joint disease.