IFIH1 and interstitial lung disease: Although the mechanisms underlying clinical phenotypes and the association between cutaneous ulceration and the pulmonary manifestations of anti-MDA5 Abs remain unknown [17], according to the findings of our study and other studies, patients with anti-MDA5 Abs have more apparent cutaneous lesions (such as cutaneous ulcerations), which may be positively correlated with aggressive pulmonary involvement (including RP-ILD or acute interstitial pneumonia), than those patients with anti-Jo-1 Abs.