Anti-mitochondrial Autoantibodies Are Associated with Cardiomyopathy, Dysphagia, and Features of More Severe Disease in Adult-onset Myositis

Sara Sabbagh¹, Iago Pinal-Fernandez², Maria Casal-Dominguez³, Jemima Albayda⁴, Julie Paik⁴, Frederick W. Miller², Lisa G. Rider⁵, Andrew Mammen³ and Lisa Christopher-Stine⁴, ¹Medical College of Wisconsin, Fox Point, WI, ²National Institutes of Health, Bethesda, MD, ³NIH, Bethesda, MD, ⁴Johns Hopkins University, Baltimore, MD, ⁵Environmental Autoimmunity Group, Clinical Research Branch, NIEHS, NIH, Garrett Park, MD

Meeting: ACR Convergence 2020

Keywords: Autoantibody(ies), Myositis

Session Information

Date: Sunday, November 8, 2020

Session Title: Muscle Biology, Myositis & Myopathies Poster

Session Type: Poster Session C

Session Time: 9:00AM-11:00AM

Background/Purpose: We examined the prevalence of anti-mitochondrial autoantibodies (AMA) in adult- and juvenile-onset myositis longitudinal cohorts and investigated phenotypic differences between myositis patients with or without AMA.

Methods: We screened sera from myositis patients who were classified as adult- or juvenile-onset dermatomyositis (DM, JDM), polymyositis (PM, JPM), inclusion body myositis (IBM), or amyopathic DM, including 619 adults and 371 children, compared to healthy controls (64 adults and 92 children), for AMA by ELISA. Clinical characteristics were compared between myositis patients with and without AMA.

Results: AMA were present in 5% of adult myositis patients (16 DM, 10 PM, 4 IBM, 1 amyopathic DM), 1% of juvenile myositis patients (3 JDM, 1 JPM), and 1% of adult and juvenile healthy control subjects. In patients with adult-onset myositis, AMA were associated with persistent muscle weakness (90% vs 62%, p=0.005), DM-specific rashes (60% vs 41%, p=0.04), Raynaud’s phenomenon (43% vs 14%, p< 0.001), dysphagia (63% vs 36%, p=0.003), and cardiomyopathy (16% vs 5%, p=0.01). Adult myositis patients with AMA may have more severe or treatment refractory disease, as they more frequently received glucocorticoids (90% vs 67%, p=0.04), intravenous immunoglobulin (IVIG) (60% vs 29%, p=0.003), and overall received a higher total number of medications, including glucocorticoids, mycophenolate mofetil, methotrexate, IVIG, azathioprine, rituximab and cyclophosphamide, (2.8 vs 2.0, p=0.002) than those who were AMA negative. In juvenile myositis, children with AMA often had falling episodes (4/4) and dysphagia (3/4), but no other clinical features or medication usage were significantly associated with AMA.

Conclusion: AMA are present in 5% of adult myositis patients and associated with cardiomyopathy, dysphagia, persistent weakness, vasomotor instability, and additional therapy. The prevalence of AMA is not increased in patients with juvenile myositis compared to age-matched controls. These data suggest that the presence of AMA in adult myositis patients should prompt screening for cardiac and swallowing involvement.

Disclosure: S. Sabbagh, None; I. Pinal-Fernandez, None; M. Casal-Dominguez, None; J. Albayda, None; J. Paik, None; F. Miller, None; L. Rider, NIEHS, NIH, 2, Cure JM Foundation, 2, Bristol Myers Squibb, 2, Hope Pharmaceuticals, 2, Eli Lilly and Company, 9, MedImmune/AstraZeneca, 9; A. Mammen, None; L. Christopher-Stine, None.

To cite this abstract in AMA style:

Sabbagh S, Pinal-Fernandez I, Casal-Dominguez M, Albayda J, Paik J, Miller F, Rider L, Mammen A, Christopher-Stine L. Anti-mitochondrial Autoantibodies Are Associated with Cardiomyopathy, Dysphagia, and Features of More Severe Disease in Adult-onset Myositis [abstract]. Arthritis Rheumatol. 2020; 72 (suppl 10). https://acrabstracts.org/abstract/anti-mitochondrial-autoantibodies-are-associated-with-cardiomyopathy-dysphagia-and-features-of-more-severe-disease-in-adult-onset-myositis/. Accessed January 18, 2021.

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