Immunoglobulin G4-associated cholangitis: Dominating immunoglobulin G4-positive clones within the B-cell receptor repertoire indicate light at the end of a long tunnel

摘要

Recently, immunoglobulin (Ig)G4-associated cholangitis (IAC) has been described as a new disease entity of the intra- and extrahepatic bile ducts leading to strictures that are difficult to distinguish from primary sclerosing cholangitis (PSC) and bile duct cancer. In contrast to PSC, these strictures disappear after corticosteroid therapy. In these patients, serum IgG4 levels are often, but not always, elevated and IgG4+ B cells and plasma cells are significantly increased in inflamed tissue. IAC is also often associated with autoimmune pancreatitis (AIP). IAC, AIP together with other IgG4-associated syndromes, are currently summarized under the spectrum of so-called IgG4-related disease (IgG4RD) (Table I).1 IgG4RD is regarded as a systemic disorder with different manifestations, such as IAC and AIP, but also affecting other organs, such as salivary glands, periorbital tissues, kidneys, and protaste (Table I).2" AIP is often not diagnosed until the tissue is analyzed by a pathologist subsequent to pancreatectomy performed because of suspected malignancy. The various syndromes of IgG4RD are characterized by tumefactive lesions, dense lymphoplasmacytic infiltrates rich in IgG4+ plasma cells, storiform fibrosis, often, but not always, elevated IgG4 serum levels, and a usually good response to corticosteroid treatment.