Detection of antibody to M2 mitochondrial antigen in Chinese patients with primary biliary cirrhosis.
BACKGROUND
Antimitochondrial antibodies (AMA) are present in more than 90% of patients with primary biliary cirrhosis (PBC). However, AMA are not specific for PBC; they can be observed in nonhepatic disease. It has been reported that antibody of M2 mitochondrial antigen (anti-M2) is specific for PBC. The aim of the present study is to clarify the role of anti-M2 in the diagnosis of PBC.


METHODS
Sera from 27 patients with PBC, 62 normal subjects, 18 patients with chronic hepatitis B and 30 patients with chronic hepatitis C were obtained for the detection of anti-M2 and AMA. The anti-M2 assay was performed by enzyme immunoassay (EIA) and the AMA test was performed by indirect immunofluorescent method.


RESULTS
Twenty-four (88.9%) of the serum specimens from the patients with PBC and one (0.9%) of the 110 serum specimens from the non-PBC groups were positive for AMA. In contrast, twenty-five (92.6%) of the 27 PBC sera and five (4.5%) of the 110 non-PBC sera were positive for anti-M2. Most of the PBC sera contained high titers of anti-M2 and all the false-negative specimens disclosed low titers of anti-M2.


CONCLUSIONS
Although the anti-M2 assay used in the present study seemed not superior to the conventional AMA test in the sense of specificity, it had the advantage of being able to provide quantitative results. Since the presence of high titer anti-M2 is very specific for PBC, this assay may have a role in the diagnosis of equivocal PBC.
Chan
C Y
CY
Department of Medicine, Veterans General Hospital-Taipei, Taiwan, R.O.C.
Huang
Y S
YS
Wu
J C
JC
Lu
R H
RH
Hwang
S J
SJ
Wang
Y J
YJ
Lee
S D
SD
D000328:Adult; D000368:Aged; D044466:Asian People; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D005260:Female; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology*
D001323:Autoantibodies; D001324:Autoantigens