Detection of antimitochondrial autoantibodies in immunofluorescent AMA-negative patients with primary biliary cirrhosis using recombinant autoantigens

Hepatology. 2001 Aug;34(2):243-8. doi: 10.1053/jhep.2001.26514.


Antimitochondrial antibodies (AMA) are the serologic hallmark of primary biliary cirrhosis (PBC). However, depending on the clinical laboratory, from 5% to 17% of PBC patients are consistently AMA-negative, using native mitochondrial antigens and a variety of conventional assays including immunofluorescence (IMF) and enzyme-linked immunosorbent assay (ELISA). The major immunoreactive mitochondrial autoantigens are the E2 members of the 2-oxo-acid dehydrogenase complex family, including pyruvate dehydrogenase complex-E2 (PDC-E2), branched chain 2-oxo acid dehydrogenase complex-E2 (BCOADC-E2), and oxo-glutarate dehydrogenase complex-E2 (OGDC-E2); cDNAs of these proteins have now been cloned, sequenced, and their B-cell epitopes defined. In the present study, we cloned cDNAs encoding these proteins from human, not bovine, sources, and expressed the recombinant proteins in a newly developed ELISA that employs a unique Escherichia coli buffer, and compared the data with previous assays using both AMA-positive and -negative patients. Using this new assay and our criteria for positive as an optical density (OD) greater than 10 SD above the mean of control sera, the AMA-positive rate of 191 PBC sera was 94% (179 of 191) compared with 84% (161 of 191) by IMF. None of the 316 control sera were reactive. Using our recombinant assays, we focused attention on the 30 IMF-AMA-negative patients. Twenty-two of 30 (73%) of these patients were positive using this new ELISA. The group of 30 IMF-AMA-negative/ELISA-positive patients did not differ significantly from a comparable population of IMF-AMA-positive patients with respect to age, sex distribution, liver function tests, elevation of serum IgM, or pathologic stage.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Autoantibodies / analysis*
  • Autoantigens / immunology*
  • Blotting, Western
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Liver Cirrhosis, Biliary / immunology*
  • Male
  • Middle Aged
  • Mitochondria / immunology*
  • Recombinant Proteins
  • Sensitivity and Specificity


  • Autoantibodies
  • Autoantigens
  • Epitopes
  • Recombinant Proteins