IFIH1 and dermatomyositis: When ELISAs were used to detect anti-MDA5 antibodies in cases of DM, classic DM, and CADM, high specificity (all specificity = 1.00) and low sensitivity (0.18 vs. 0.13 vs. 0.46, respectively) were observed, thereby suggesting that the presence of anti-MDA5 antibodies may not be an appropriate screening index for these diseases.