Since the anti-MDA5 antibodies were never detected in IIP patients who did not exhibit DM manifestations, even though 18 of them had been diagnosed with RP-ILD, the production of these antibodies appears to be tightly associated with RP-ILD in the context of DM, but not with RP-ILD alone. This evidence concerns the gene IFIH1 and idiopathic interstitial pneumonia.