As shown in Figure 6B, the increased protein expression of IRF7 (1.13 ± 0.32 vs. 0.79 ± 0.18, p = 0.0336), STAT1 (1.14 ± 0.30 vs. 0.66 ± 0.20, p = 0.0055), STAT2 (1.12 ± 0.36 vs. 0.56 ± 0.10, p = 0.0234), p-STAT1 (1.00 ± 0.27 vs. 0.57 ± 0.19, p = 0.0063), and p-STAT2 (1.03 ± 1.16 vs. 0.64 ± 0.09, p = 0.0001) was shown in the PBMCs of patients with IIM, and this altered protein expression mode represents the activation of IFN-I signaling and downstream JAK–STAT pathways. Here, STAT2 is linked to acquired idiopathic inflammatory myopathy.