Quantitative measurement of autoantibodies to recombinant mitochondrial antigens in patients with primary biliary cirrhosis: relationship of levels of autoantibodies to disease progression.

We examined the clinical usefulness of measurements of antimitochondrial autoantibodies (AMA) in predicting disease progression in patients with primary biliary cirrhosis (PBC). We determined the relationships between AMA levels measured by indirect immunofluorescence (IF) and those measured by quantitative enzyme immunoassays (EIAs) using recombinant 2-oxo-acid dehydrogenase complex (2-OADC) proteins and the Mayo Risk Score, an established indicator of disease progression in primary biliary cirrhosis (PBC). Results of tests for AMA by either method correlated weakly (r = .24 to .30) with disease progression as indicated by Mayo Risk Scores. The levels of AMA to 2-OADC proteins varied by more than 200-fold between patients but remained relatively constant over time in individual patients. Despite being positively correlated with Mayo Risk Score results, the levels of AMA to 2-OADC proteins were not useful for predicting disease progression in individual patients with PBC. In addition, we found no significant differences in the levels of autoantibodies to 2-OADC proteins among patients with different histological stages of disease. Our results show that measurements of AMA by IF or by quantitative EIA methods with recombinant 2-OADC proteins are not useful parameters for predicting disease progression in patients with PBC.