Clinical diagnostic criteria of autoimmune pancreatitis: revised proposal

In 1961, Sarles et al. 1 asked the following question regarding the particular cases of pancreatitis with hypergammaglobulinemia: “Chronic inflammatory sclerosis of the pancreas—an autoimmune pancreatic disease?” As similar cases were rarely observed, a relationship between such pancreatitis and autoimmunity was viewed skeptically during the following several decades. In 1992, Toki et al. 2 have reported 4 cases with unusual diffuse irregular narrowing of the main pancreatic duct and diffuse enlargement of the entire pancreas due to lymphocyte infiltration. In 1995, Japanese investigators 3 firstly proposed a concept of “autoimmune pancreatitis (AIP)”, in which the patients showed diffusely enlarged pancreas, narrowing pancreatogram, increased serum IgG, presence of autoantibodies, fibrotic changes with lymphocytic infiltration and steroidal efficacy. Thereafter, many AIP cases have been reported from Japan, and AIP has been accepted as a new clinical entity. 4 , 5 The histopathological findings of AIP show massive infiltration of lymphoplasmacytes with fibrosis, which is consistent with lymphoplasmacytic sclerosing pancreatitis (LPSP). 6 Many Japanese investigators have paid great attention to AIP, especially with regard to its unique pancreatic images, 2 IgG4, 7 disease-associated autoantibodies, 8 extrapancreatic lesions, 6 , 9 – 14 and steroidal efficacy. 14 , 15