Clinical spectrum and management

IgG4-related disease (IgG4-RD) is a relatively newly described disease entity. Autoimmune pancreatitis is its most widely recognized and best characterized manifestation. However, extrapancreatic lesions are common, such as cholangitis and retroperitoneal fibrosis. The term IgG₄-related sclerosing cholangitis (IgG₄-SC) biliary manifestation of IgG4-RD. Biliary strictures diagnosed and treated with steroids early in the course of IgG4-SC can resolve after successful therapy. This feature defines IgG₄-SC which is histologically characterized by infiltration by IgG4-positive plasma cells. Though biliary strictures have been found to resolve with steroids, relapse is common. The long-term outcome is unclear. According to current guidelines, serum IgG4 levels should be measured in all patients with possible primary sclerosing cholangitis (PSC), to rule out IgG₄-SC. PSC patients with elevated IgG4 levels seem to have a worse prognosis than those with normal IgG4 levels.