%0 Journal Article
%T Type 1 Autoimmune Pancreatitis Can Transform into Chronic Pancreatitis: A Long-Term Follow-Up Study of 73 Japanese Patients
%A Masahiro Maruyama
%A Norikazu Arakura
%A Yayoi Ozaki
%A Takayuki Watanabe
%A Tetsuya Ito
%A Suguru Yoneda
%A Masafumi Maruyama
%A Takashi Muraki
%A Hideaki Hamano
%A Akihiro Matsumoto
%A Shigeyuki Kawa
%J International Journal of Rheumatology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/272595
%X Some patients with autoimmune pancreatitis (AIP) form pancreatic stones suggestive of transformation into chronic pancreatitis (CP). The present study examined the underlying risk factors and mechanism of AIP progression to confirmed CP. We compared the clinical and laboratory parameters of subjects who progressed to confirmed CP with those of the subjucts who did not in a cohort of 73 type 1 AIP patients. A total of 16 (22%) AIP patients progressed to CP. Univariate analysis revealed that relapse was significantly more frequent in the progression group, and multivariate analysis indicated that pancreatic head swelling (OR 12.7, ) and nonnarrowing of the main pancreatic duct in the pancreatic body (OR 12.6, ) were significant independent risk factors for progression to CP. Kaplan-Meier testing showed that the progression rate to CP was approximately 10% at 3 years and 30% at 10 years in total AIP patients and 30% at 3 years and 60% at 10 years in subjects with both risk factors. AIP with pancreatic head swelling and a history of relapse may cause pancreatic juice stagnation and nonnarrowing of the main pancreatic duct in the pancreatic body, which can progress to advanced stage chronic pancreatitis. 1. Introduction Autoimmune pancreatitis (AIP) has been recognized as a distinctive type of pancreatitis possibly caused by autoimmune mechanisms [1¨C3]. Recently, AIP was classified into type 1 and type 2 based on the pathological differences, in which type 1 was designated as lymphoplasmacytic sclerosing pancreatitis (LPSP) and type 2 as idiopathic duct centric chronic pancreatitis (IDCP) or AIP with granulocytic epithelial lesion (GEL) [4¨C7]. Although the International Consensus Diagnostic Criteria (ICDC) [8] first enabled us to diagnose type 1 and type 2 AIP, AIP in Japan has revealed to be type 1 AIP exclusively. Along with this, all AIP patients in our institution have been diagnosed with type 1 by ICDC, and we have focused on the clinical study for type 1 AIP. Accordingly, in this paper, we dealt with type 1 AIP as AIP. AIP is characterized by pancreatic enlargement and irregular narrowing of the main pancreatic duct (MPD), both of which resemble the imaging features of pancreatic cancer [9, 10]. Other characteristic features of AIP include high serum IgG4 and IgG4-positive plasma cell infiltration in affected pancreatic tissue, which are used in serological and pathological AIP diagnosis, respectively [11, 12]. As patients with AIP respond favorably to prednisolone (PSL) therapy, the disease was previously believed to be a nonprogressive condition that
%U http://www.hindawi.com/journals/ijr/2013/272595/