title: Eosinophilia and allergic disorders in autoimmune pancreatitis.
abstract: OBJECTIVE
  In autoimmune pancreatitis (AIP), the prevalence, interrelationships, and significance of peripheral eosinophilia, allergic disorders, and eosinophil infiltration in the pancreas remain unclear.
  
  
  METHODS
  From medical records, we obtained data on peripheral eosinophil counts at presentation and follow-up, and clinical diagnoses of allergic disorders in 97 AIP patients (78 type 1 and 19 type 2), which were compared with matched healthy controls. Available pancreatic histologic specimens were graded for eosinophils. Peripheral eosinophilia was defined as counts >0.5×10(9) per liter. We examined nature of and association between these parameters in AIP.
  
  
  RESULTS
  Among 78 type 1 AIP patients (mean age 62±14 years, 77% men), peripheral eosinophilia at presentation was diagnosed in 12% and allergic disorders in 15% (vs. 0 and 4% in controls, P=0.0004 and 0.006, respectively). Allergic disorders were observed in 27 and 11% of type 1 AIP with and without eosinophilia, respectively (P=0.08). Patients with and without peripheral eosinophilia were similar in clinical profile. Moderate-to-severe eosinophil infiltration was present in 67% of pancreas resection specimens and did not correlate with peripheral eosinophilia. Type 2 AIP did not differ from type 1 AIP in any of these parameters.
  
  
  CONCLUSIONS
  Peripheral eosinophilia, allergic disorders, and pancreatic eosinophil infiltration are associated with AIP. Eosinophilia in AIP may not reflect an allergic phenomenon, but appears to be consistent with autoimmune mechanism.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Raghuwansh P
authors.initials: RP
authors.lastname: Sah
authors.forename: Rahul
authors.initials: R
authors.lastname: Pannala
authors.forename: Lizhi
authors.initials: L
authors.lastname: Zhang
authors.forename: Rondell P
authors.initials: RP
authors.lastname: Graham
authors.forename: Aravind
authors.initials: A
authors.lastname: Sugumar
authors.forename: Suresh T
authors.initials: ST
authors.lastname: Chari
mesh_terms: D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000453:epidemiology* / Q000473:pathology; D015897:Comorbidity; D004802:Eosinophilia / Q000453:epidemiology* / Q000473:pathology; D004804:Eosinophils / Q000473:pathology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000473:pathology; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D018709:Statistics, Nonparametric