IGHG3 and interstitial lung disease: When MDA5+ DM-ILD patients were sorted into RP-ILD and non-RP-ILD subgroups, the combinations of anti-MDA5 IgG1 IgG2, IgG1 IgG3, IgG1 IgG4, and IgG1 IgG2 IgG3 were 14, 19, 10, and 0% in the RP-ILD group, compared to 6, 0, 4, and 2% in the non-RP-ILD group (Fig. 2B).