IFNA4 and dermatomyositis: Notably, the mRNA levels of the type I-III IFNs examined were significantly upregulated in the DM patients (IFN-α2, HC vs. DM, P < 0.01; IFN-α4, HC vs. DM, P < 0.05; IFN-β1, HC vs. DM, P < 0.0001; IFN-γ, HC vs. DM, P < 0.01; and IFN-λ1, HC vs. DM, P < 0.05).