Anti-mitochondrial autoantibodies are associated with cardiomyopathy, dysphagia, and features of more severe disease in adult-onset myositis

Abstract

We analyzed the prevalence of anti-mitochondrial autoantibodies (AMA) in adult- and juvenile-onset myositis longitudinal cohorts and investigated phenotypic differences in myositis patients with AMA. We screened sera from myositis patients including 619 adult- and 371 juvenile-onset dermatomyositis (DM, JDM), polymyositis (PM, JPM), inclusion body myositis (IBM), or amyopathic DM patients and from healthy controls, including 164 adults and 92 children, for AMA by ELISA. Clinical characteristics were compared between myositis patients with and without AMA. AMA were present in 5% of adult myositis patients (16 of 216 DM, 10 of 222 PM, 4 of 140 IBM, 1 of 19 amyopathic DM), 1% of juvenile myositis patients (3 of 302 JDM, 1 of 25 JPM), and 1% of both adult and juvenile healthy controls. In patients with adult-onset myositis, AMA were associated with persistent muscle weakness, Raynaud’s phenomenon, dysphagia, and cardiomyopathy. Adult myositis patients with AMA may have more severe or treatment refractory disease, as they more frequently received glucocorticoids and intravenous immunoglobulin. In juvenile myositis, children with AMA often had falling episodes and dysphagia, but no other clinical features or medications were significantly associated with AMA. AMA are present in 5% of adult myositis patients and associated with cardiomyopathy, dysphagia, and other signs of severe disease. The prevalence of AMA is not increased in patients with juvenile myositis compared to age-matched healthy controls. Our data suggest that the presence of AMA in adult myositis patients should prompt screening for cardiac and swallowing involvement. Key Points• Approximately 5% of a large North American cohort of adult myositis patients have anti-mitochondrial autoantibodies.• Adults with anti-mitochondrial autoantibodies often have chronic weakness, Raynaud’s, dysphagia, cardiomyopathy, and more severe disease.• Anti-mitochondrial autoantibodies are rare in juvenile myositis and not associated with a specific clinical phenotype.

Juvenile dermatomyositis. Where are we now?

“…The authors found that 1% (4 of 371) of children with JDM and healthy controls (1 of 92) had AMA detected by ELISA. All 4 JDM patients with AMA had severe disease at onset with falling episodes and 3 out of the 4 had dysphagia (85). Though the detection of AMA was shown to be very rare in JDM patient sera this study suggested that it may predict worse disease for these patients.…”

Anti‐mitochondrial antibodies in Indian patients with idiopathic inflammatory myopathies

“…AMA positivity was not recorded in any of the children included in the cohort. A recent study showed that 1% of the juvenile myositis cases (3 of 302 jDM, 1 of 25 jPM) tested positive for AMA although they did not have any cardiac involvement 24 . Literature is sparse on this subject and requires further study from pediatric centers.…”

The Emerging Role of Mitochondrial Dysfunction in the Pathogenesis of Idiopathic Inflammatory Myopathies

“…On the other hand, dysphagia was noticed as significantly more frequent both in AMA-positive adults and children. 124 The authors stated, as a conclusion, that detection of AMA should instigate physicians to monitor for cardiac and gastroesophageal dysfunction.…”