Immunoglobulin G4-related disease (IgG4-RD) is an uncommon inflammatory disorder that may affect multiple organ systems, including the biliary tree. IgG4-sclerosing cholangitis (IgG4-SC) can be difficult to distinguish from primary sclerosing cholangitis (PSC) or cholangiocarcinoma (CCA). The investigators aim to evaluate the sensitivity and specificity of bile for the diagnosis of IgG4-SC. Bile samples of patients with biliary strictures of various causes, including IgG4-SC, PSC, and CCA, will be collected during clinical cholangiography procedures. IgG4 will be measured in bile specimens and bile IgG4 concentrations compared between IgG4-SC, PSC, CCA, and other types of biliary strictures.

This study will recruit cases from Mayo Clinic Rochester and Japanese institutions such as Nagoya City University Hospital, Nagoya Daini Red Cross Hospital, and Kurashiki Central hospital. Participants will be individuals who will receive endoscopic retrograde cholangiography (ERC), endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) or percutaneous transhepatic cholangiography (PTC). Bile samples collected from the target cases will be assayed for IgG4 concentration.

Inclusion Criteria:

• The presence of a biliary stricture
• 18 years and older
• Consented to IRB 707-03

Exclusion Criteria:

• Younger than 18 years of age
• Unable to collect a bile sample
• Abnormal postsurgical anatomy preventing collection of a bile sample

Cases with biliary stricture(s) of any cause

Data sharing could be arranged and will require IRB approval