ObjectivePancreatic autoantibodies (PABs), comprising antibodies against glycoprotein 2 (anti-GP2), are typically associated with complicated phenotypes in Crohn's disease, but have also been observed with variable frequencies in patients with UC. In a previous study, we observed a high frequency of primary sclerosing cholangitis (PSC) in patients with anti-GP2-positive UC. We therefore aimed to characterise the role of anti-GP2 in PSC.DesignIn an evaluation phase, sera from 138 well-characterised Norwegian patients with PSC were compared with healthy controls (n=52), and patients with UC without PSC (n=62) for the presence of PABs by indirect immunofluorescence. Further, 180 German patients with PSC served as a validation cohort together with 56 cases of cholangiocarcinoma without PSC, 20 of secondary sclerosing cholangitis (SSC) and 18 of autoimmune hepatitis.ResultsAnti-GP2 IgA specifically occurred at considerable rates in large bile duct diseases (cholangiocarcinoma=36%, PSC and SSC about 50%). In PSC, anti-GP2 IgA consistently identified patients with poor survival during follow-up (Norwegian/German cohort: p Log Rank=0.016/0.018). Anti-GP2 IgA was associated with the development of cholangiocarcinoma in both PSC cohorts, yielding an overall OR of cholangiocarcinoma in patients with anti-GP2 IgA-positive PSC of 5.0 (p=0.001). Importantly, this association remained independent of disease duration, bilirubin level and age.ConclusionsAnti-GP2 IgA can be hypothesised as a novel marker in large bile duct diseases. In particular, in PSC, anti-GP2 IgA identified a subgroup of patients with severe phenotype and poor survival due to cholangiocarcinoma. Anti-GP2 IgA may therefore be a clinically valuable tool for risk stratification in PSC.

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Endogenous circadian clocks regulate 24-h rhythms of physiology and behavior. Circadian rhythm disruption (CRD) is suggested as a risk factor for inflammatory bowel disease. However, the underlying molecular mechanisms remain unknown. Intestinal biopsies from Per1/2 mutant and wild-type (WT) mice were investigated by electron microscopy, immunohistochemistry, and bromodeoxyuridine pulse-chase experiments. TNF-α was injected intraperitoneally, with or without necrostatin-1, into Per1/2 mice or rhythmic and externally desynchronized WT mice to study intestinal epithelial cell death. Experimental chronic colitis was induced by oral administration of dextran sodium sulfate. , caspase activity was assayed in Per1/2-specific small interfering RNA-transfected cells. was overexpressed to study antiapoptosis and the cell cycle. Genetic ablation of circadian clock function or environmental CRD in mice increased susceptibility to severe intestinal inflammation and epithelial dysregulation, accompanied by excessive necroptotic cell death and a reduced number of secretory epithelial cells. Receptor-interacting serine/threonine-protein kinase (RIP)-3-mediated intestinal necroptosis was linked to increased mitotic cell cycle arrest Per1/2-controlled Wee1, resulting in increased antiapoptosis cellular inhibitor of apoptosis-2. Together, our data suggest that circadian rhythm stability is pivotal for the maintenance of mucosal barrier function. CRD increases intestinal necroptosis, thus rendering the gut epithelium more susceptible to inflammatory processes.-Pagel, R., Bär, F., Schröder, T., Sünderhauf, A., Künstner, A., Ibrahim, S. M., Autenrieth, S. E., Kalies, K., König, P., Tsang, A. H., Bettenworth, D., Divanovic, S., Lehnert, H., Fellermann, K., Oster, H., Derer, S., Sina, C. Circadian rhythm disruption impairs tissue homeostasis and exacerbates chronic inflammation in the intestine.

Although a great variety of new drugs have been introduced for the therapy of inflammatory bowel diseases so far, a definite cure of the disease is still out of scope. An anti-inflammatory approach to induce remission followed by maintenance therapy with immunosupressants is still the mainstay of therapy. Thiopurines comprising azathioprine and its active metabolite mercaptopurine as well as tioguanine, are widely used in the therapy of chronic active inflammatory bowel disease (IBD). Their steroid sparing potential and efficacy in remission maintenance are out of doubt. Unfortunately, untoward adverse events are frequently observed and may preclude further administration or be life threatening. This review will focus on new aspects of thiopurine therapy in IBD, its efficacy and safety.