Associations between anti-mitochondrial antibodies and cardiac involvement in idiopathic inflammatory myopathy patients

Anti-mitochondrial antibody–mediated myopathy with cardiac involvement

“…AMAs were not detected in serum until years after the first finding of elevated creatine kinase 1 year after implantation of the pacemaker, and they were not documented in either muscle or endo-myocardial biopsy. Although the specificity of AMA for cardiac involvement was 92% in a recent meta-analysis 2 and the I 2 value for these analyses was >50%, it was concluded that, according to diagnostic odds ratio (DOR) analysis, the overall pooled accuracy was not high enough to draw definitive conclusions on the pathogenicity of AMA in IIM-related cardiomyopathy. 2 Whether AMAs were already present in the index patient at initial presentation for arrhythmias remains speculative, as they were not determined.…”

“…Although the specificity of AMA for cardiac involvement was 92% in a recent meta-analysis 2 and the I 2 value for these analyses was >50%, it was concluded that, according to diagnostic odds ratio (DOR) analysis, the overall pooled accuracy was not high enough to draw definitive conclusions on the pathogenicity of AMA in IIM-related cardiomyopathy. 2 Whether AMAs were already present in the index patient at initial presentation for arrhythmias remains speculative, as they were not determined. It is also not mentioned whether the index patient has been tested for myositis-specific antibodies (MSAs) or myositis auto-antibodies (MAAs) other than AMA, such as anti PL-7, anti-PL-12, SRP, TIF1-γ, anti-NXP2, anti-SAE, MDA5, ANA, HMGCR, or anti-Ro/SSA.…”

“…The major limitation of the study is that the index patient was not genetically tested. Because AMA can be a non-specific finding, according to a recent meta-analysis of 171 patients with idiopathic, inflammatory myopathy (IIM), 2 it is crucial that primary (hereditary) myopathy, particularly mitochondrial myopathy, is adequately ruled out. To rule out hereditary myopathy, it is essential not only to carry out whole-exome sequencing (WES) or a panel investigation for myopathy and cardiomyopathy but also to take a detailed family history.…”

Anti-mitochondrial antibody–mediated myopathy with cardiac involvement: reply

“…Second, AMA has never been associated with mitochondrial myopathy. 4 Although he showed recent meta-analysis, 5 it merely evaluated the diagnostic value of AMA for cardiac involvement in idiopathic inflammatory myopathies (IIMs), not its pathogenicity.…”