Autoimmune pancreatitis

Two distinct subtypes of autoimmune pancreatitis (AIP) are lymphoplasmacytic sclerosing pancreatitis or type 1 AIP and idiopathic duct centric pancreatitis or type 2 AIP. This chapter focuses on type 1 AIP, often simply referred to as AIP, followed by a contrast with the distinguishing features of type 2 AIP. The fact that B-cell depletion with rituximab is an effective treatment for the induction and maintenance of remission for AIP highlights the crucial role of B cells in pathogenesis of AIP. The primary differential diagnosis for AIP is pancreatic cancer. An international working group has formulated consensus diagnostic criteria, for both type 1 and type 2 AIP, to facilitate both clinical management and research. The result of these efforts is the International Consensus Diagnostic Criteria, which include the following criteria: pancreatic duct imaging, pancreatic parenchymal imaging, serum IgG4 level, histology, other organ involvement, and response to steroid therapy.