We found that compared to HDs, the frequency of GZMK+GZMB− CD4 T cells was significantly increased in MDA5+DM patients (HDs vs. MDA5+DM: 0.45 ± 0.28% vs. 1.34 ± 0.94%, P = 0.0202), and the frequency of GZMK−GZMB+ CD4 T cells was significantly decreased in MDA5+DM patients (HDs vs. MDA5+DM: 6.30 ± 3.93% vs. 3.12 ± 3.35%, P = 0.0093) (Figure 3A). Here, IFIH1 is linked to dermatomyositis.