Immunoglobulin G4-associated cholangitis: one variant of immunoglobulin G4-related systemic disease

IgG4-associated cholangitis (IAC) is a recently defined disease entity which shares a number of clinical, biochemical, and radiological features with primary sclerosing cholangitis (PSC). In contrast to PSC, IAC responds to immunosuppressive treatment, is not associated with inflammatory bowel disease, and mainly affects elderly men above the age of 60 years. Today, IAC is regarded as one variant of IgG4-related systemic disease (ISD) of which autoimmune pancreatitis (AIP) is the best studied organ manifestation. The diagnosis of IAC is based on biochemical, radiological and histologic features, among which elevated serum levels of IgG4, extra- and intrahepatic biliary strictures as visualized by cholangiography, multifocal IgG4-rich lymphoplasmacytic sclerosing infiltrations in liver and bile duct tissue, and association with AIP are of key importance. This review aims at summarizing clinical features, diagnostic criteria, therapeutic strategies and most recent insights in the pathophysiology of IAC and other organ manifestations of ISD.