title: Regulatory T cells in type 1 autoimmune pancreatitis.
abstract: Autoimmune pancreatitis (AIP) is a newly recognized pancreatic disorder. Recently, International Consensus Diagnostic Criteria for AIP (ICDC) was published. In this ICDC, AIP was classified into Type 1 and Type 2. Patients with Type 1 AIP have several immunologic and histologic abnormalities specific to the disease, including increased levels of serum IgG4 and storiform fibrosis with infiltration of lymphocytes and IgG4-positive plasmacytes in the involved organs. Among the involved organs showing extrapancreatic lesions, the bile duct is the most common, exhibiting sclerosing cholangitis (IgG4-SC). However, the role of IgG4 is unclear. Recently, it has been reported that regulatory T cells (Tregs) are involved in both the development of various autoimmune diseases and the shift of B cells toward IgG4, producing plasmacytes. Our study showed that Tregs were increased in the pancreas with Type 1 AIP and IgG4-SC compared with control. In the patients with Type 1 AIP and IgG4-SC, the numbers of infiltrated Tregs were significantly positively correlated with IgG4-positive plasma cells. In Type 1 AIP, inducible costimulatory molecule (ICOS)(+) and IL-10(+) Tregs significantly increased compared with control groups. Our data suggest that increased quantities of ICOS(+) Tregs may influence IgG4 production via IL-10 in Type 1 AIP.
authors.affiliation: Department of Gastroenterology and Hepatology, Kansai Medical University, 10-15 Fumisono Cho, Moriguchi, Osaka 570-8506, Japan.
authors.forename: Kazushige
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authors.lastname: Uchida
authors.forename: Takeo
authors.initials: T
authors.lastname: Kusuda
authors.forename: Masanori
authors.initials: M
authors.lastname: Koyabu
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyoshi
authors.forename: Norimasa
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authors.lastname: Fukata
authors.forename: Kimi
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authors.lastname: Sumimoto
authors.forename: Yuri
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authors.lastname: Fukui
authors.forename: Yutaku
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authors.lastname: Sakaguchi
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ikeura
authors.forename: Masaaki
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authors.lastname: Shimatani
authors.forename: Toshiro
authors.initials: T
authors.lastname: Fukui
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Matsushita
authors.forename: Makoto
authors.initials: M
authors.lastname: Takaoka
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Nishio
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Okazaki