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

Iago Pinal-Fernandez, Christopher A. Mecoli, Maria Casal-Dominguez, Katherine Pak, Yuji Hosono, Julio Huapaya, Wilson Huang, Jemima Albayda, Eleni Tiniakou, Julie J. Paik, Cheilonda Johnson, Sonye K. Danoff, Andrea M. Corse, Lisa Christopher-Stine, Andrew L. Mammen

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)e1768-e1777
Issue number19
StatePublished - Nov 5 2019

ASJC Scopus subject areas

  • Clinical Neurology


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