Immunoglobulin G4-associated cholangitis

Immunoglobulin G4-associated cholangitis is a recently identified clinical entity characterized by infiltration of immunoglobulin G4 -bearing plasma cells in bile ducts and other affected tissues. This review is focused mainly on the most recent studies published during the last 2 years that have increased our understanding of this clinical entity.

Investigations concerning the immune mechanisms, liver histology in immunoglobulin G4-associated cholangitis and reports of clinical and radiological features of the condition as well as medical therapy are discussed.

Immunoglobulin G4-associated cholangitis was found to be characterized by overproduction of T helper 2 cells, and regulatory cytokines (interleukin-10 and transforming growth factor-beta) were upregulated in the affected tissues. Immunoglobulin G4 immunostaining in a range of clinically involved tissues in patients with immunoglobulin G4-associated cholangitis and autoimmune pancreatitis was found to be important for diagnostic purposes, which is probably most useful in cases with normal immunoglobulin G4 levels. It has become apparent that multiple measurements of immunoglobulin G4 levels in patients with clinically suspected immunoglobulin G4-associated cholangitis are important, revealing abnormally high levels in patients with normal immunoglobulin G4 on initial testing. Most patients respond to steroids initially but disease relapse seems to be common. A significant proportion of primary sclerosing cholangitis patients have elevated immunoglobulin G4 levels.