METHODS:BACKGROUND & AIMS:Lifetime risk of biliary tract cancer (BTC) in primary sclerosing cholangitis (PSC) exceeds 20% and BTC is currently the leading cause of death in PSC patients. To open new avenues for management, we aimed to delineate novel and clinically relevant genomic and pathological features of a large panel of PSC-associated BTC (PSC-BTC). APPROACH & RESULTS:We analysed formalin fixed, paraffin embedded tumor tissue from 186 PSC-BTC patients from 11 centers in eight countries with all anatomical locations included. We performed tumor DNA sequencing at 42 clinically relevant genetic loci to detect mutations, translocations and copy number variations, along with histomorphological and immunohistochemical characterization. Irrespective of the anatomical localization, PSC-BTC exhibited a uniform molecular and histological characteristic similar to extrahepatic cholangiocarcinoma. We detected a high frequency of genomic alterations typical of extrahepatic cholangiocarcinoma, e.g. TP53 (35.5%), KRAS (28.0%), CDKN2A (14.5%), and SMAD4 (11.3%), as well as potentially druggable mutations (e.g. HER2/ERBB2). We found a high frequency of non-typical/non-ductal histomorphological subtypes (55.2%) and of the usually rare BTC precursor lesion, intraductal papillary neoplasia (18.3%) CONCLUSION: Genomic alterations in PSC-BTC include a significant number of putative actionable therapeutic targets. Notably, PSC-BTC show a distinct extrahepatic morpho-molecular phenotype, independent of the anatomical location of the tumor. These findings advance our understanding of PSC-associated cholangiocarcinogenesis and provide strong incentives for clinical trials to test genome-based personalized treatment strategies in PSC-BTC.

METHODS:BACKGROUND:The impact of inflammatory bowel disease (IBD) activity on long-term outcomes after liver transplantation (LT) for primary sclerosing cholangitis (PSC) is unknown. We examined the impact of post-LT IBD activity on clinically significant outcomes. METHODS:One hundred twelve patients undergoing LT for PSC from 2 centers were studied for a median of 7 years. Patients were divided into 3 groups according to their IBD activity after LT: no IBD, mild IBD, and moderate to severe IBD. Patients were classified as having moderate to severe IBD if they met at least 1 of 3 criteria: (i) Mayo 2 or 3 colitis or Simple Endoscopic Score-Crohn's Disease ≥7 on endoscopy; (ii) acute flare of IBD necessitating steroid rescue therapy; or (iii) post-LT colectomy for medically refractory IBD. RESULTS:Moderate to severe IBD at any time post-transplant was associated with a higher risk of Clostridium difficile infection (27% vs 8% mild IBD vs 8% no IBD; P = 0.02), colorectal cancer/high-grade dysplasia (21% vs 3% both groups; P = 0.004), post-LT colectomy (33% vs 3% vs 0%) and rPSC (64% vs 18% vs 20%; P < 0.001). Multivariate analysis revealed that moderate to severe IBD increased the risk of both rPSC (relative risk [RR], 8.80; 95% confidence interval [CI], 2.81-27.59; P < 0.001) and colorectal cancer/high-grade dysplasia (RR, 10.45; 95% CI, 3.55-22.74; P < 0.001). CONCLUSIONS:Moderate to severe IBD at any time post-LT is associated with a higher risk of rPSC and colorectal neoplasia compared with mild IBD and no IBD. Patients with no IBD and mild IBD have similar post-LT outcomes. Future prospective studies are needed to determine if more intensive treatment of moderate to severe IBD improves long-term outcomes in patients undergoing LT for PSC.

METHODS::T cells from patients with primary sclerosing cholangitis (PSC) show a prominent IL-17 response upon stimulation with bacteria or fungi, yet the reasons for this dominant TH17 response in PSC are not clear. Here, we analyzed the potential role of monocytes in microbial recognition and in skewing the T cell response towards Th17. Monocytes and T cells from blood and livers of PSC patients and controls were analyzed ex vivo and in vitro using trans-well experiments with cholangiocytes. Cytokine production was measured using flow cytometry, ELISA, RNA in situ hybridization and quantitative real time PCR. Genetic polymorphisms were obtained from Immunochip analysis. Following ex vivo stimulation with PMA/Ionomycin, PSC patients showed significantly increased numbers of IL-17A-producing peripheral blood CD4+ T cells compared to PBC patients and healthy controls, indicating increased Th17 differentiation in vivo. Upon stimulation with microbes, monocytes from PSC patients produced significantly more IL-1β and IL-6, cytokines known to drive Th17 cell differentiation. Moreover, microbe-activated monocytes induced the secretion of Th17 and monocyte-recruiting chemokines CCL-20 and CCL-2 in human primary cholangiocytes. In livers of patients with PSC cirrhosis, CD14hi CD16int and CD14lo CD16hi monocytes/macrophages were increased compared to alcoholic cirrhosis and monocytes were found to be located around bile ducts. Conclusion: PSC patients show increased Th17 differentiation already in vivo. Microbe-stimulated monocytes drive Th17 differentiation in vitro and induce cholangiocytes to produce chemokines mediating recruitment of Th17 cells and more monocytes into portal tracts. Taken together, these results point to a pathogenic role of monocytes in patients with PSC.