More prominent muscle involvement in patients with dermatomyositis with anti-Mi2 autoantibodies

Neurology. 2019 Nov 5;93(19):e1768-e1777. doi: 10.1212/WNL.0000000000008443. Epub 2019 Oct 8.


Objective: To define the clinical phenotype of dermatomyositis (DM) with anti-Mi2 autoantibodies.

Methods: In this longitudinal cohort study, the prevalence and severity of clinical features at disease onset and during follow-up in patients with anti-Mi2-positive DM were compared to patients with anti-Mi2-negative DM, antisynthetase syndrome (AS), and immune-mediated necrotizing myopathy (IMNM). Longitudinal anti-Mi2 autoantibody titers were assessed.

Results: A total of 58 patients with anti-Mi2-positive DM, 143 patients with anti-Mi2-negative DM, 162 patients with AS, and 170 patients with IMNM were included. Among patients with anti-Mi2-positive DM, muscle weakness was present in 60% at disease onset and occurred in 98% during longitudinal follow-up; fewer patients with anti-Mi2-negative DM developed weakness (85%; p = 0.008). Patients with anti-Mi2-positive DM were weaker and had higher creatine kinase (CK) levels than patients with anti-Mi2-negative DM or patients with AS. Muscle biopsies from patients with anti-Mi2-positive DM had prominent necrosis. Anti-Mi2 autoantibody levels correlated with CK levels and strength (p < 0.001). With treatment, most patients with anti-Mi2-positive DM had improved strength and CK levels; among 10 with multiple serum samples collected over 4 or more years, anti-Mi2 autoantibody titers declined in all and normalized in 3, 2 of whom stopped immunosuppressant treatment and never relapsed. Patients with anti-Mi2-positive DM had less calcinosis (9% vs 28%; p = 0.003), interstitial lung disease (5% vs 16%; p = 0.04), and fever (7% vs 21%; p = 0.02) than did patients with anti-Mi2-negative DM.

Conclusions: Patients with anti-Mi2-positive DM have more severe muscle disease than patients with anti-Mi2-negative DM or patients with AS. Anti-Mi2 autoantibody levels correlate with disease severity and may normalize in patients who enter remission.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Autoantibodies / immunology*
  • Calcinosis / epidemiology*
  • Calcinosis / physiopathology
  • Case-Control Studies
  • Cohort Studies
  • Creatine Kinase / blood
  • Dermatomyositis / blood
  • Dermatomyositis / epidemiology
  • Dermatomyositis / immunology*
  • Dermatomyositis / physiopathology
  • Female
  • Fever / epidemiology*
  • Humans
  • Longitudinal Studies
  • Lung Diseases, Interstitial / epidemiology*
  • Lung Diseases, Interstitial / physiopathology
  • Male
  • Mi-2 Nucleosome Remodeling and Deacetylase Complex / immunology*
  • Middle Aged
  • Muscle Weakness / epidemiology*
  • Muscle Weakness / physiopathology
  • Myositis / immunology
  • Myositis / physiopathology
  • Necrosis
  • Phenotype
  • Prevalence
  • Severity of Illness Index


  • Autoantibodies
  • CHD4 protein, human
  • Creatine Kinase
  • Mi-2 Nucleosome Remodeling and Deacetylase Complex

Supplementary concepts

  • Antisynthetase syndrome