Pancreatic endocrine and exocrine functions in patients with autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a distinctive type of pancreatitis, and it is considered that the pathogenesis of AIP involves autoimmune mechanisms [1–6]. Recently, AIP has been considered as a systemic disease because it is often accompanied by various extrapancreatic lesions including cholangitis, sialadenitis, retroperitoneal fibrosis, hilar lymphadenopathy, and chronic thyroiditis [7–11]. Furthermore, AIP is often associated with pancreatic exocrine and endocrine dysfunction. Recently, AIP is known to have two clinical and histological subtypes [12, 13], and the international consensus diagnostic criteria (ICDC) published in 2012 [14] enabled us to classify these subtypes into type 1 and type 2. Patients with type 1 AIP often show accompanying extrapancreatic lesions but seldom reveal abdominal pain. On the other hand, patients with type 2 AIP commonly have abdominal pain and sometimes accompany acute pancreatitis. In the present manuscript, we focus on the endocrine and exocrine functions associated with type 1 AIP according to the revised Japanese consensus guideline for management of AIP [15–17].