title: Analysis of two major anti-M2 antibodies (anti-PDC-E2/anti-BCOADC-E2) in primary biliary cirrhosis: relationship to titers of immunofluorescent anti-mitochondrial antibody.
abstract: To analyze anti-M2 components in primary biliary cirrhosis (PBC) we measured two major anti-M2 antibodies (anti-PDC-E2 and anti-BCOADC-E2) by immunoblotting and ELISA, and compared the results between 38 immunofluorescent anti-mitochondrial antibody (AMA)-negative PBC patients (group A) and 39 strongly AMA-positive PBC patients (group B) with titers of 1:640. Using bovine heart mitochondrial fraction as antigen, the immunoblot positivity rate of anti-PDC-E2 in group B was significantly higher than that in group A, whereas the positivity rate of anti-BCOADC-E2 was not significantly different between the two groups. This result was similar to that obtained by ELISA using recombinant fusion proteins. In group A there was a significant inverse correlation between ELISA optical density values of anti-PDC-E2 and of anti-BCOADC-E2, but in group B there was no correlation between the two values. Only three patients from group A and 21 from group B were positive for both antibodies. Taken together these results appear to indicate that the detection of anti-BCOADC-E2 is critical for the accurate serological diagnosis of AMA-negative PBC patients. The detection of anti-BCOADC-E2 may also help to distinguish between AMA-negative PBC and autoimmune cholangitis patients.
authors.affiliation: Fourth Department of Internal Medicine, Teikyo University School of Medicine, 3-8-3 Mizonokuchi, Takatsu-ku, Kawasaki-shi, 213-8507, Kanagawa, Japan
authors.initials: H
authors.lastname: Miyakawa
authors.initials: E
authors.lastname: Kitazawa
authors.initials: H
authors.lastname: Fujikawa
authors.initials: K
authors.lastname: Kikuchi
authors.initials: K
authors.lastname: Abe
authors.initials: N
authors.lastname: Kawaguchi
authors.initials: M
authors.lastname: Kako