Although we routinely test all serum samples from patients with inflammatory myopathies by immunoprecipitation assays using 35S-protein-labeled HeLa cells, until the development of our proposed method, we had not been able to clearly identify patients with anti-140 kDa antibodies (anti-CADM-140; i.e, anti-MDA5). This evidence concerns the gene IFIH1 and myopathy.