title: How to Diagnose Immunoglobulin G4-Associated Cholangitis: The Jack-of-All-Trades in the Biliary Tract.
abstract: BACKGROUND
  Immunoglobulin (Ig) G4-associated cholangitis (IAC) is an inflammatory disorder of the biliary tract displaying characteristic features of IgG4-related disease (IgG4-RD): elevation of IgG4 serum levels, infiltration of IgG4+ plasma cells in the affected tissue, and good response to immunosuppressive treatment.
  
  
  RESULTS
  The clinical presentation of IAC is often misleading, mimicking other diseases of the biliary tract such as cholangiocarcinoma or primary and secondary sclerosing cholangitis. The HISORt criteria form the cornerstone in the diagnosis of IAC, combining histopathological (H), imaging (I), and serological (S) features including serum IgG4, other organ manifestations (O) of IgG4-RD and response to treatment (Rt). The accuracy of the HISORt criteria is limited. Novel diagnostic approaches are under evaluation.
  
  
  CONCLUSIONS
  More accurate biomarkers are needed to correctly diagnose IgG4-RD and prevent misdiagnoses and unnecessary therapeutic interventions.
authors.affiliation: Department of Gastroenterology & Hepatology and Tytgat Institute of Liver and Intestinal Research, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Lowiek M
authors.initials: LM
authors.lastname: Hubers
authors.affiliation: Department of Gastroenterology & Hepatology and Tytgat Institute of Liver and Intestinal Research, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Beuers
keywords: CCA; Cholangiocarcinoma; IgG4-related systemic disease; PSC; Primary sclerosing cholangitis