title: Antibodies to carbonic anhydrase in patients with immune cholangiopathies.
abstract: OBJECTIVE
  Bile duct epithelia contain an abundance of carbonic anhydrase. Antibodies to this enzyme have been described in autoimmune disorders. Serum from patients with immune-mediated liver diseases was studied to determine whether antibodies to carbonic anhydrase II and/or pyruvate dehydrogenase could distinguish autoimmune cholangitis as immunologically distinct from primary biliary cirrhosis.
  
  
  METHODS
  Antibody assays to carbonic anhydrase II (Western blot) and pyruvate dehydrogenase (flow cytometry) were performed on the sera of patients with autoimmune cholangitis (6), primary biliary cirrhosis (12), primary sclerosing cholangitis (12), autoimmune hepatitis (12), and control (Gilbert syndrome; 8).
  
  
  RESULTS
  Reactivity to carbonic anhydrase II was detected in 5 of 6 patients with autoimmune cholangitis, 1 of 12 patients with primary biliary cirrhosis, 1 of 12 patients with autoimmune hepatitis, and no other patients. Individuals with autoimmune cholangitis were more likely than the other patients to be reactive to carbonic anhydrase II (P < 0.001). Patients with primary biliary cirrhosis were more reactive to pyruvate dehydrogenase compared with all other groups (P < 0.001).
  
  
  CONCLUSIONS
  An antibody to human carbonic anhydrase II is frequently detected in the sera of patients with autoimmune cholangitis and is uncommon or not present in other cholangiopathies. These data provide evidence that autoimmune cholangitis and primary biliary cirrhosis represent distinct entities with unique patterns of immunoreactivity.
authors.affiliation: Department of Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Gordon
authors.forename: T M
authors.initials: TM
authors.lastname: Quattrociocchi-Longe
authors.forename: B A
authors.initials: BA
authors.lastname: Khan
authors.forename: V P
authors.initials: VP
authors.lastname: Kodali
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: A L
authors.initials: AL
authors.lastname: Silverman
authors.forename: F L
authors.initials: FL
authors.lastname: Kiechle
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology*; D002256:Carbonic Anhydrases / Q000276:immunology*; D002761:Cholangitis / Q000276:immunology*; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000276:immunology*; D008875:Middle Aged; D011768:Pyruvate Dehydrogenase Complex / Q000276:immunology
chemical_list: D001323:Autoantibodies; D011768:Pyruvate Dehydrogenase Complex; D002256:Carbonic Anhydrases