Increased type-I interferon level is associated with liver damage and fibrosis in primary sclerosing cholangitis

Background: The level of type-I interferons (IFNs) in primary sclerosing cholangitis (PSC) was investigated to evaluate its association with disease activity and progression. Methods: Bioactive type-I IFNs were evaluated in a murine model of PSC and human patients' sera using a cell-based reporter assay and ELISA techniques. In total, 57 healthy participants, 71 PSC, and 38 patients with primary biliary cholangitis were enrolled in this study. Results: Bioactive type-I IFNs were elevated in the liver and serum of multidrug resistance protein 2-deficient animals and showed a correlation with the presence of CD45+ immune cells and serum alanine transaminase levels. Concordantly, bioactive type-I IFNs were elevated in the sera of patients with PSC as compared to healthy controls (sensitivity of 84.51%, specificity of 63.16%, and AUROC value of 0.8267). Bioactive IFNs highly correlated with alkaline phosphatase (r=0.4179, p<0.001), alanine transaminase (r=0.4704, p<0.0001), and gamma-glutamyl transpeptidase activities (r=0.6629, p<0.0001) but not with serum bilirubin. In addition, patients with PSC with advanced fibrosis demonstrated significantly higher type-I IFN values. Among the type-I IFN subtypes IFN alpha, beta and IFN omega could be detected in patients with PSC with IFN omega showing the highest concentration among the subtypes and being the most abundant among patients with PSC. Conclusions: The selectively elevated bioactive type-I IFNs specifically the dominating IFN omega could suggest a novel inflammatory pathway that might also have a hitherto unrecognized role in the pathomechanism of PSC.