Immunoglobulin G4-related cholangitis: a variant of IgG4-related systemic disease.

IgG4-related sclerosing cholangitis as part of IgG4 systemic-related diseases is commonly associated with autoimmune pancreatitis. Major clinical manifestations of IgG4-related sclerosing diseases are apparent in the organs in which tissue fibrosis with obstructive phlebitis is pathologically induced. IgG4-related sclerosing cholangitis is included within the heterogeneous group of 'sclerosing cholangitis'. Sclerosing cholangitis may be associated with choledocholithiasis, infection or biliary malignancies. Sclerosing cholangitis of unknown etiology is called primary sclerosing cholangitis (PSC). Conservative therapy of PSC is usually unsuccessful, the disease involves extra- and/or intrahepatic biliary tree, and the end point of this disease is liver cirrhosis. Typically, PSC is identified at the age of 30 to 40 years, and the disease is frequently associated with inflammatory bowel diseases. On the other hand, IgG4-related sclerosing cholangitis is not associated with inflammatory bowel diseases. In patients with IgG4-related sclerosing cholangitis, a first symptom can be obstructive jaundice, whereas obstructive jaundice is rarely present in PSC. Clinically, patients with IgG4-related sclerosing cholangitis are older at diagnosis compared to patients with PSC. A typical diagnostic feature of IgG4-related sclerosing cholangitis is elevation of serum immunoglobulin G4. In patients with IgG4-related sclerosing cholangitis, response to steroid therapy is high; in patients with PSC corticosteroid therapy is unsuccessful. Histochemically abundant infiltration of IgG4-positive plasma cells is detected in the biliary duct wall. Histologically, we can identify dense lymphoplasmacytic infiltration of the bile duct wall, transmural fibrosis, lymphoplasmacytic infiltration and fibrosis in the periportal area of the liver - a typically obliterative phlebitis. The biliary epithelium is usually intact in contrast to PSC, where mucosal erosion is often present. Steroids are the first-choice therapy of IgG4-related sclerosing cholangitis. In the literature, cholangiocarcinoma in patients with IgG4- related sclerosing cholangitis was not described, whereas cholangiocarcinoma develops in up to 10-30% of patients with PSC.