Ankylosing spondylitis and bowel disease.

Clinical studies indicate an important role for bowel inflammation in ankylosing spondylitis and other spondyloarthropathies whereby two different aspects have to be considered. First, the gut inflammation is clinically and histologically closely related to Crohn's disease. Recent data on subclinical immune alterations confirm this relationship and suggest that spondyloarthropathy is a unique human model for studying early Crohn's disease. Second, bowel and peripheral joint inflammation are clinically, histologically and pathogenetically linked. The most important clinical implication of these observations is that targeted therapies for Crohn's disease could also be effective for intestinal as well as extra-intestinal disease manifestations in spondyloarthropathy, as evidenced by the recent studies on TNF-alpha blockade. Unravelling the gut-synovium axis in spondyloarthopathy could also contribute to the identification of new therapeutic targets. Finally, assessment of subclinical gut inflammation by histology, serology and genetics could contribute to the stratification of individual patients in subgroups with an optimal response to specific therapeutic interventions.