J
John 'The Man
Guest
Autoreactivity to lipoate and a conjugated form of lipoate in primary biliary cirrhosis.
Bruggraber SF, Leung PS, Amano K, Quan C, Kurth MJ, Nantz MH, Benson GD, Van de Water J, Luketic V,
Roche TE, Ansari AA, Coppel RL, Gershwin ME.
Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis Medical
School, 95616, USA.
BACKGROUND & AIMS: Although considerable effort has been directed toward the mapping of peptide
epitopes by autoantibodies, the role of nonprotein molecules has been less well studied. The
immunodominant autoantigen in primary biliary cirrhosis (PBC), E2 components of pyruvate
dehydrogenase complexes (PDC-E2), has a lipoate molecule bonded to the domain to which
autoantibodies are directed. METHODS: We examined sera from patients with PBC (n = 105), primary
sclerosing cholangitis (n = 70), and rheumatoid arthritis (n = 28) as well as healthy volunteers (n
= 43) for reactivity against lipoic acid. The lipoic acid hapten specificity of the reactive
antibodies in PBC sera was determined following incubation of aliquots of the sera with human serum
albumin (HSA), lipoylated HSA (HSA-LA), PDC-E2, lipoylated PDC-E2, polyethylene glycol (PEG),
lipoylated PEG, free lipoic acid, and synthetic molecular mimics of lipoic acid. RESULTS: Anti-
lipoic acid specific antibodies were detected in 81% (79 of 97) of antimitochondrial antibody (AMA)-
positive patients with PBC but not in controls. Two previously unreported specificities in AMA-
positive sera that recognize free lipoic acid and a carrier-conjugated form of lipoic acid were also
identified. CONCLUSIONS: We hypothesize that conjugated form(s) of native or xenobiotic lipoic acid
mimics contribute to the initiation and perpetuation of autoimmunity by at first breaking self-
tolerance and participating in subsequent determinant spreading. The variability in the
immunoreactive carrier/lipoate conjugates provides an experimental framework on which potential
mechanisms for the breakdown of self-tolerance following exposure to xenobiotics can be
investigated. The data have implications for patients taking lipoic acid as a dietary supplement.
PMID: 14724823 [PubMed - indexed for MEDLINE] Gastroenterol Hepatol. 2004 Feb;27(2):47-50.
Bruggraber SF, Leung PS, Amano K, Quan C, Kurth MJ, Nantz MH, Benson GD, Van de Water J, Luketic V,
Roche TE, Ansari AA, Coppel RL, Gershwin ME.
Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis Medical
School, 95616, USA.
BACKGROUND & AIMS: Although considerable effort has been directed toward the mapping of peptide
epitopes by autoantibodies, the role of nonprotein molecules has been less well studied. The
immunodominant autoantigen in primary biliary cirrhosis (PBC), E2 components of pyruvate
dehydrogenase complexes (PDC-E2), has a lipoate molecule bonded to the domain to which
autoantibodies are directed. METHODS: We examined sera from patients with PBC (n = 105), primary
sclerosing cholangitis (n = 70), and rheumatoid arthritis (n = 28) as well as healthy volunteers (n
= 43) for reactivity against lipoic acid. The lipoic acid hapten specificity of the reactive
antibodies in PBC sera was determined following incubation of aliquots of the sera with human serum
albumin (HSA), lipoylated HSA (HSA-LA), PDC-E2, lipoylated PDC-E2, polyethylene glycol (PEG),
lipoylated PEG, free lipoic acid, and synthetic molecular mimics of lipoic acid. RESULTS: Anti-
lipoic acid specific antibodies were detected in 81% (79 of 97) of antimitochondrial antibody (AMA)-
positive patients with PBC but not in controls. Two previously unreported specificities in AMA-
positive sera that recognize free lipoic acid and a carrier-conjugated form of lipoic acid were also
identified. CONCLUSIONS: We hypothesize that conjugated form(s) of native or xenobiotic lipoic acid
mimics contribute to the initiation and perpetuation of autoimmunity by at first breaking self-
tolerance and participating in subsequent determinant spreading. The variability in the
immunoreactive carrier/lipoate conjugates provides an experimental framework on which potential
mechanisms for the breakdown of self-tolerance following exposure to xenobiotics can be
investigated. The data have implications for patients taking lipoic acid as a dietary supplement.
PMID: 14724823 [PubMed - indexed for MEDLINE] Gastroenterol Hepatol. 2004 Feb;27(2):47-50.