PM-Scl-75 is the main autoantigen in patients with the polymyositis/scleroderma overlap syndrome

Arthritis Rheum. 2004 Feb;50(2):565-9. doi: 10.1002/art.20056.


Objective: To compare the autoantigenicity of the recently described N-terminally elongated PM-Scl-75 protein with that of PM-Scl-100 and the originally defined PM-Scl-75 polypeptide, and to determine its value for analyzing sera from patients with the polymyositis (PM)/scleroderma overlap syndrome.

Methods: Serum samples obtained from patients with the PM/scleroderma overlap syndrome and from patients with several other diseases were analyzed for the presence of autoantibodies reactive with recombinant PM-Scl-100 and PM-Scl-75 (both the original and the longer form) proteins, in an enzyme-linked immunosorbent assay (ELISA).

Results: Autoantibodies recognizing the longer PM-Scl-75 protein isoform were detected in 28% of the patients with PM/scleroderma. This percentage is slightly higher than that for PM-Scl-100 (25%) and is significantly higher than that for the previously defined PM-Scl-75 protein (11%). In addition, we identified a significant number of patients who had anti-PM-Scl-75 but not anti-PM-Scl-100 antibodies. This finding contrasts with what has been previously reported for the shorter version of the PM-Scl-75 protein.

Conclusion: Our data indicate that use of the long PM-Scl-75 isoform in addition to PM-Scl-100 in ELISAs significantly increases the number of patients in whom anti-PM-Scl autoantibodies can be detected.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantigens / immunology*
  • Autoimmune Diseases / immunology*
  • Exoribonucleases
  • Exosome Multienzyme Ribonuclease Complex
  • Humans
  • Nuclear Proteins / classification
  • Nuclear Proteins / immunology*
  • Polymyositis / complications
  • Polymyositis / immunology*
  • Recombinant Proteins
  • Scleroderma, Systemic / complications
  • Scleroderma, Systemic / immunology*
  • Syndrome


  • Autoantigens
  • Nuclear Proteins
  • Recombinant Proteins
  • Exoribonucleases
  • Exosome Multienzyme Ribonuclease Complex
  • EXOSC10 protein, human