Fig 2: Anti-mitochondrial antibodies in JDM are associated with calcinosis. Levels of anti-mitochondrial antibodies (AMA) were assessed using an in-house flow cytometry assay. (A) Comparison of AMA levels in healthy controls (HC), juvenile SLE (jSLE), polymyositis (PM), RNP + overlap syndrome, and juvenile dermatomyositis (JDM). Further stratification was done based on myositis-specific autoantibodies (MSA). Data are presented as (A) median fluorescence intensity (MFI)and (B) percent positive patients, based on 95th percentile of healthy controls (dotted line). (C) Patients were stratified based on prior history of calcinosis (Calc+) or not (Calc-) and assessed for AMA levels. (D) AMA levels measured in JDM patients without history of calcinosis (Calc-), as well as patients with history of calcinosis with blood samples taken either prior (Calc + pre) or after (Calc + post) clinical manifest calcification. All graphs: Median is shown. Statistical analysis: A and C: Non-parametric Mann-Whitney test. B: Chi2 test. D: Wilcoxon matched-pairs signed rank test. *p < 0.05, **p < 0.01, and ***p < 0.001. The ‘floating’ significance asterisks signify comparisons to healthy controls, whereas the lined significance compares the groups under the line.