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Clinical characteristics of patients with myositis and autoantibodies to different fragments of the Mi-2β antigen
  1. G J D Hengstman1,
  2. W T M Vree Egberts2,
  3. H P Seelig3,
  4. I E Lundberg4,
  5. H M Moutsopoulos5,
  6. A Doria6,
  7. M Mosca7,
  8. J Vencovsky8,
  9. W J van Venrooij2,
  10. B G M van Engelen1
  1. 1Neuromuscular Centre Nijmegen, Department of Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands and Institute for Fundamental and Clinical Human Movement Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
  2. 2Department of Biochemistry, Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
  3. 3Institute of Immunology and Molecular Genetics, Karlsruhe, Germany
  4. 4Rheumatology Unit, Department of Medicine, Karolinska University Hospital, Solna, Karolinska Institutet, Stockholm, Sweden
  5. 5Department of Pathophysiology, School of Medicine, National University of Athens, Athens, Greece
  6. 6Division of Rheumatology, University of Padova, Padova, Italy
  7. 7Rheumatology Unit, Department of Internal Medicine, University of Pisa, Pisa, Italy
  8. 8Institute of Rheumatology, Prague, Czech Republic
  1. Correspondence to:
    Dr G J D Hengstman
    Neuromuscular Centre Nijmegen, Department of Neurology, University Medical Centre Nijmegen, PO Box 9101, Internal Code 935, 6500 HB Nijmegen, The Netherlands; g.hengstman{at}neuro.umcn.nl

Abstract

Objectives: To assess the clinical implications of autoantibodies directed against different parts of the Mi-2β autoantigen in patients with myositis.

Methods: A systematic assessment of the clinical, laboratory, and histological characteristics of 48 anti-Mi-2 positive patients from six European centres was made. Anti-Mi-2 autoantibodies were determined with an ELISA using four overlapping fragments spanning the entire amino acid sequence of the autoantigen. Data were compared with results for a large group of anti-Mi-2 negative patients with myositis published previously.

Results: Anti-Mi-2 autoantibodies were found in dermatomyositis, polymyositis, and inclusion body myositis. In general, myositis with anti-Mi-2 autoantibodies was characterised by relatively mild disease, sometimes accompanied by extramuscular symptoms, including arthralgia, arthritis, Raynaud’s phenomenon, and interstitial lung disease. Cardiac disease was not seen, and treatment response was fair. No differences were found between patients with autoantibodies to different fragments of the Mi-2β antigen, except for a potentially increased risk of cancer in patients with antibodies directed to the N-terminal fragment of the autoantigen.

Conclusions: Anti-Mi-2 autoantibodies are not a marker of a specific subtype of myositis. No significant differences between patients with autoantibodies to different fragments of the Mi-2β autoantigen are found, with the possible exception of an increased risk of cancer in patients with antibodies to the N-terminal fragment.

  • DM, dermatomyositis
  • ELISA, enzyme linked immunosorbent assay
  • IBM, inclusion body myositis
  • MSAs, myositis-specific autoantibodies
  • PM, polymyositis
  • autoantibodies
  • anti-Mi-2
  • polymyositis
  • dermatomyositis
  • inclusion body myositis

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Footnotes

  • Conflict: None of the authors have a conflict of interest to declare.

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