1.9 Comparison of the Clinical Presentations of Ty...
Hart et al.（2013a）reported an international collaborative study of 1064 patients with AIP（978（91.9%）type 1 AIP and 86（8.1%）type 2 AIP）diagnosed according to the ICDC.Patients with type 2 AIP were diagnosed at younger ages than those with type 1 AIP（average:61.4 years in type 1 AIP subjects and 39.9 years in type 2 subjects）.The proportion of males was higher in type 1 AIP patients（77%）than in type 2 patients（55%）.The proportion of patients with type 2 AIP was significantly higher in Europe（12.9%）than in Asia（3.7%）.Remission could be induced in almost all cases with type 1 and type 2 AIP.Relapses were more common in patients with type 1 AIP（30.9%）than in those with type 2 AIP（9.3%）.Hart et al.（2015a）also reported the clinical features of 43 patients with type 2 AIP（31 definitive and 12 probable cases）treated at the Mayo Clinic in the United States.Twenty five out of the 43（58.1%）patients developed acute pancreatitis，12/43（27.9%）patients had recurrent pancreatitis，and 15/43（34.9%）patients had pancreatic mass/obstructive jaundice.The cumulative relapse rate was 10.6%at 3 years（median follow-up period of 2.9 years）.In Japan，Notohara et al.（2015）compared the clinical features of patients with type 1 AIP and type 2 AIP in Japan.They showed that type 2 AIP patients were younger and had more frequent abdominal pain and increased serum pancreatic enzymes than those with type 1 AIP.Obstructive jaundice，elevated serum IgG and IgG4，the presence of autoantibodies，association of IgG4-related diseases including sclerosing cholangitis，diabetes mellitus，and imaging findings of extrapancreatic biliary dilatation and intrapancreatic biliary strictures were more common in patients with type 1 AIP than in type 2 AIP.(https://www.daowen.com)