The link between autoimmunity and cancer immunosurveillance during cholangitis and cholangiocarcinoma

Bile duct cancer or cholangiocarcinoma (CCA) is the second most common primary liver tumor. The arsenal of treatments for CCA is highly limited due to the resistance to standard chemo-radiotherapies and to the low resection efficiency. Chronic inflammation is a well-known risk factor for cancer development, and two chronic inflammatory diseases of the bile ducts are characterized: primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Hence, PSC is the 1st etiology established of CCA in Western countries. In contrast, patients with PBC never develop CCA. Based on this observation, we hypothesized that PBC- associated autoimmunity would fuel CCA immunosurveillance and protect the patients from its emergence. In our mouse models, we observed that PBC reduced the frequency of tumor onset and delayed the tumor growth kinetic. Conversely, PSC did not impact the progression of the CCA. We demonstrated that this protection was CCA-specific and did not have any effects on others tumor histotypes. It was also dependent on CD4 and CD8 T lymphocytes and B cells. Altogether, these results evidence a mechanistic overlapping between autoimmunity and cancer immunosurveillance, with autoimmune reactions against organ-specific self-antigens contributing to the elimination of malignant cells originating from the same tissue.