Autoantibodies against a 43 KDa muscle protein in inclusion body myositis

PLoS One. 2011;6(5):e20266. doi: 10.1371/journal.pone.0020266. Epub 2011 May 23.


Background: Inclusion body myositis (IBM) is a poorly understood and refractory autoimmune muscle disease. Though widely believed to have no significant humoral autoimmunity, we sought to identify novel autoantibodies with high specificity for this disease.

Methodology/principal findings: Plasma autoantibodies from 65 people, including 25 with IBM, were analyzed by immunoblots against normal human muscle. Thirteen of 25 (52%) IBM patient samples recognized an approximately 43 kDa muscle protein. No other disease (N = 25) or healthy volunteer (N = 15) samples recognized this protein.

Conclusions: Circulating antibodies against a 43-kDa muscle autoantigen may lead to the discovery of a novel biomarker for IBM. Its high specificity for IBM among patients with autoimmune myopathies furthermore suggests a relationship to disease pathogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Autoantibodies / immunology*
  • Autoantigens / immunology
  • Autoantigens / metabolism*
  • Female
  • Humans
  • Immunoblotting
  • Male
  • Middle Aged
  • Muscle Proteins / immunology
  • Muscle Proteins / metabolism*
  • Myositis, Inclusion Body / metabolism*
  • Young Adult


  • Autoantibodies
  • Autoantigens
  • Muscle Proteins