title: Detection of autoantibody against carbonic anhydrase II in various liver diseases by enzyme-linked immunosorbent assay using appropriate conditions.
abstract: BACKGROUND
  Immunoglobulin G autoantibody against carbonic anhydrase (CA) II has been detected in the sera of patients with a variety of autoimmune diseases. Antibody against CAII has also been described as a serological marker for distinguishing between cases of autoimmune cholangitis (AIC) and those of primary biliary cirrhosis (PBC). However, the optimal antibody measurement conditions (enzyme-linked immunosorbent assay: ELISA) have not yet been established. Moreover, we also found that a small amount of an IgG-like material exists in purchased CAII reagents, which causes pseudopositive reactions.
  
  
  METHODS
  The sera of 96 patients with liver disease were examined for the presence of anti-CAII antibody using antigen (CAII) not containing the IgG-like material as the most suitable measurement conditions. Compared with the anti-CAII antibody prevalence of 3.8% found in normal subjects, a significantly higher seroprevalence of the antibody was detected in patients with PBC (31.0%, P<0.02), autoimmune hepatitis (AIH) (50.0%, P<0.01) and chronic viral hepatitis (27.5%, P<0.01). But, in cases of PBC, no significant correlation was noted between the level of anti-CAII antibody and the presence of anti-mitochondrial antibodies (AMA).
  
  
  CONCLUSIONS
  While CAII may be a target antigen in autoimmune diseases, the anti-CAII antibody is not likely to be a specific marker of AIC. The optimum measurement conditions for the ELISA for anti-CAII antibody would provide us with valuable information to elucidate the underlying immunological abnormalities in liver diseases.
authors.affiliation: Division of Clinical Laboratory Medicine, Tokyo-Kosei-Nenkin Hospital, Shinjuku, Tokyo, Japan. yamame@sol.dti.ne.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosoda
authors.forename: Masako
authors.initials: M
authors.lastname: Okawa-Takatsuji
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Shu
authors.initials: S
authors.lastname: Uwatoko
authors.forename: Shinichi
authors.initials: S
authors.lastname: Aotsuka
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: D001323:Autoantibodies / Q000097:blood*; D024402:Carbonic Anhydrase II / Q000097:blood / Q000276:immunology*; D002761:Cholangitis / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay; D019693:Hepatitis, Autoimmune / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology; D006525:Hepatitis, Viral, Human / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000097:blood; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology; D008107:Liver Diseases / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology*; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D024402:Carbonic Anhydrase II