IFIH1 and interstitial lung disease: In patients with PM/DM and anti-MDA5 antibody, 53.3–82% of them have CADM [80,88,89,90], 94–95% have ILD [88,89], and 71–84% show rapidly progressive ILD [88] or acute/subacute (within 3 months) onset of ILD [80], which has a poor prognosis.