Autoantibodies specific for alpha-enolase in systemic autoimmune disorders

J Rheumatol. 2000 Jan;27(1):109-15.

Abstract

Objective: To analyze the presence and specificity of anti-alpha-enolase antibodies in various systemic autoimmune diseases.

Methods: Sera from patients with systemic lupus erythematosus (SLE), mixed cryoglobulinemia (MC), systemic sclerosis (SSc), and rheumatoid arthritis (RA) were tested by immunoblot on partially purified a-enolase from human kidney and on beta- and gamma-enolase. The isotype of anti-enolase antibodies was determined by means of isotype-specific monoclonal antibodies.

Results: IgG anti-alpha-enolase antibodies were detected in 9/33 (27%) SLE sera (6/9 patients had active renal disease), in 6/19 sera from patients with MC and nephritis, in 0/15 sera from MC patients without renal involvement, in 6/20 (30%) SSc sera, in 2/35 (6%) disease controls with RA, and in 2/32 (6%) healthy controls. The antibodies were not species-specific, but in most cases were specific for the alpha isoform of enolase. The anti-enolase immune response was not isotypically restricted. In half of the patients with SLE the anti-alpha-enolase and anti-DNA antibodies constituted distinct antibody populations, while in the other half a partial overlap of the 2 antibody specificities was observed.

Conclusion: Anti-alpha-enolase antibodies can frequently be detected in systemic autoimmune disorders. In SLE and MC they are associated with nephritis and in SSc they are associated with severe endothelial damage. Alpha-enolase is ubiquitous, but is highly expressed in the kidney and also on the membrane of several cell types including endothelial cells. Thus, anti-alpha-enolase antibodies could contribute to renal injury not only by the local formation of immune complexes, but also by direct damage to endothelial cells.

MeSH terms

  • Adult
  • Aged
  • Amino Acid Sequence
  • Arthritis, Rheumatoid / blood*
  • Autoantibodies / blood*
  • Cryoglobulinemia / blood*
  • Female
  • Humans
  • Isoenzymes / immunology
  • Lupus Erythematosus, Systemic / blood*
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Phosphopyruvate Hydratase / immunology*
  • Scleroderma, Systemic / blood*
  • Sensitivity and Specificity

Substances

  • Autoantibodies
  • Isoenzymes
  • Phosphopyruvate Hydratase