The gut-adherent microbiota of PSC-IBD is distinct to that of IBD.

Primary sclerosing cholangitis–IBD (PSC–IBD) is an inflammatory autoimmune hepato–biliary–enteric disease in which it is predicted that gut microbiota have potential pathophysiological effects, relevant to disease initiation and outcome. The recent article by Kummen et al 1 who reported that the gut microbiota in PSC is distinct compared with those from healthy controls and patients with UC without liver disease, is therefore of interest. However, it remains unclear if these alterations in the gut microbiota are a cause or an effect of liver disease, and there remains a challenging task to link dysbiosis with disease pathogenesis, as well as clarify whether faecal microbiota are entirely representative of communities of mucosa-associated bacteria, which might uniquely interact with immune and epithelial cells. Nevertheless Kummen et al notably demonstrated that the Veillonella genus showed a marked increase in PSC–IBD, in comparison with both healthy controls and patients with UC alone. Given interest in the mechanism of lymphocyte tracking between the bowel and liver …