title: Differences in clinical profile and relapse rate of type 1 versus type 2 autoimmune pancreatitis.
abstract: OBJECTIVE
  Autoimmune pancreatitis (AIP) has been divided into subtypes 1 (lymphoplasmacytic sclerosing pancreatitis) and 2 (idiopathic duct centric pancreatitis). We compared clinical profiles and long-term outcomes of types 1 and 2 AIP.
  
  
  METHODS
  We compared clinical presentation, relapse, and vital status of 78 patients with type 1 AIP who met the original HISORt criteria and 19 patients with histologically confirmed type 2 AIP.
  
  
  RESULTS
  At presentation, patients with type 1 AIP were older than those with type 2 AIP (62 +/- 14 vs 48 +/- 19 years; P < .0001) and had a greater prevalence of increased serum levels of immunoglobulin G4 (47/59 [80%] vs 1/6 [17%]; P = .004). Patients with type 1 were more likely than those with type 2 to have proximal biliary, retroperitoneal, renal, or salivary disease (60% vs 0; P < .0001). Inflammatory bowel disease was associated with types 1 and 2 (6% vs 16%; P = .37). During median clinical follow-up periods of 42 and 29 months, respectively, 47% of patients with type 1 and none of those with type 2 experienced a relapse. In type 1 AIP, proximal biliary involvement (hazard ratio [HR], 2.12; P = .038) and diffuse pancreatic swelling (HR, 2.00; P = .049) were predictive of relapse, whereas pancreaticoduodenectomy reduced the relapse rate (vs the corticosteroid-treated group; HR, 0.15; P = .0001). After median follow-up periods of 58 and 89 months (types 1 and 2, respectively), the 5-year survival rates for both groups were similar to those of the age- and sex-matched US population.
  
  
  CONCLUSIONS
  Types 1 and 2 AIP have distinct clinical profiles. Patients with type 1 AIP have a high relapse rate, but patients with type 2 AIP do not experience relapse. AIP does not affect long-term survival.
authors.affiliation: Fiterman Center for Digestive Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Raghuwansh P
authors.initials: RP
authors.lastname: Sah
authors.forename: Suresh T
authors.initials: ST
authors.lastname: Chari
authors.forename: Rahul
authors.initials: R
authors.lastname: Pannala
authors.forename: Aravind
authors.initials: A
authors.lastname: Sugumar
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Clain
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Levy
authors.forename: Randall K
authors.initials: RK
authors.lastname: Pearson
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Smyrk
authors.forename: Bret T
authors.initials: BT
authors.lastname: Petersen
authors.forename: Mark D
authors.initials: MD
authors.lastname: Topazian
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Michael B
authors.initials: MB
authors.lastname: Farnell
authors.forename: Santhi S
authors.initials: SS
authors.lastname: Vege
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000145:classification* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016577:Pancreaticoduodenectomy; D050500:Pancreatitis, Chronic / Q000145:classification* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D016016:Proportional Hazards Models; D012008:Recurrence