title: Potential for differential diagnosis of autoimmune pancreatitis and pancreatic cancer using carbonic anhydrase II antibody.
abstract: OBJECTIVE
  Pancreatic ductal epithelia contain an abundance of carbonic anhydrase (CA), and the presence of antibodies to this enzyme has been described in autoimmune disorders. We previously found a small amount of an immunoglobulin G-like material in purchased CAII reagents, which led to pseudopositive reactions.
  
  
  METHODS
  We determined the optimum measurement conditions for detecting anti-CAII antibody using an enzyme-linked immunosorbent assay and sera from 140 patients with pancreatic diseases.
  
  
  RESULTS
  Compared with the prevalence of anti-CAII antibody in healthy subjects, a significantly higher seroprevalence of the antibody was detected in patients with autoimmune pancreatitis (AIP) (88.9%, P < 0.02), Sjögren syndrome (67.6%, P < 0.01), and alcoholic chronic pancreatitis (45.8%, P < 0.01). No positive results were obtained among patients with pancreatic cancer. Moreover, the antibody value obtained in the pancreatic cancer patients was actually lower than that obtained in healthy subjects.
  
  
  CONCLUSIONS
  The anti-CAII antibody is probably not a specific marker of AIP because it was present at a higher frequency in the sera of patients with other pancreatic diseases. Nevertheless, the anti-CAII antibody may be a useful tool for the differential diagnosis of AIP and pancreatic cancer.
authors.affiliation: Department of Clinical Laboratory Medicine, Tokyo-Kosei-Nenkin Hospital, Tokyo, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosoda
authors.forename: Masako
authors.initials: M
authors.lastname: Okawa-Takatsuji
authors.forename: Wahei
authors.initials: W
authors.lastname: Shinmura
authors.forename: Naoaki
authors.initials: N
authors.lastname: Hasimoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ozaki
authors.forename: Yusei
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology; D024402:Carbonic Anhydrase II / Q000276:immunology*; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007564:Japan; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology*; D010195:Pancreatitis / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology; D019512:Pancreatitis, Alcoholic / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology; D012859:Sjogren's Syndrome / Q000175:diagnosis* / Q000201:enzymology* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D024402:Carbonic Anhydrase II