Serum immunoglobin G4 (IgG4): an important marker in autoimmune pancreatitis?

A unique form of chronic pancreatitis has recently become widely recognised as an important clinical entity in the spectrum of pancreatic diseases under the term autoimmune pancreatitis (AIP). This entity is characterised by irregular narrowing of the pancreatic duct, swelling of parenchyma, lymphoplasmacytic infiltration and fibrosis as well as favourable response to corticosteroid treatment. In addition, increased concentration of serum immunoglobulin G4 (IgG4) is a notable characteristic marker. Some patients undergoing pancreaticoduodenectomy for presumed pancreatic ductal adenocarcinoma have instead been found to have AIP. Early recognition of AIP can prevent pancreaticoduodenectomy in these patients and effective treatment with steroids can be introduced. Based on an interesting case, we discuss the entity of AIP with the rare combination of sclerosing cholangitis and we focus on the relevance of serum IgG4 as a factor in diagnosis and monitoring therapy of AIP.