IFNB1 and dermatomyositis: Correlation between IFNs levels and disease activity showed that PGA was strongly correlated with type-I IFNs, IFN-α (r=0.76 [0.60-0.86], p<0.001) and IFN-β (r=0.58 [0.35-0.74], p<0.01) in DM.