Primary sclerosing cholangitis and inflammatory bowel disease: a complicated yet unique relationship

Primary sclerosing cholangitis (PSC) is a rare liver disorder characterized by biliary ducts inflammation, fibrosis and consequently chronic cholestasis, which progressively lead to liver cirrhosis. The main feature of PSC is the frequent association with inflammatory bowel disease (IBD), with an estimated prevalence of around 70% of the cases. This strong relationship seems due to the presence of shared pathogenetic mechanisms, which seem to involve the intestinal barrier function, the human gut microbiota and the immune innated and adaptative response to antigens derived from the bowel. Of relevance, PSC-IBD have specific clinical and pathological features that differ from PSC and IBD as separate entities, explaining the diversity in outcomes among these categories, and therefore the distinct clinical management that is required. The aim of this review is to present recent data regarding the epidemiology, pathobiology and clinical features of PSC-IBD.