TLR7 and rheumatic disorder: As shown in Fig. 1G, an increased level of TLR7 mRNA was revealed in the PBMCs of patients with HCV infection, particularly those with MC symptoms (10.6 ± 3.4-fold), compared to those without MC symptoms (4.1 ± 1.1-fold, P < 0.005), rheumatic patients without HCV infection (1.8 ± 0.7-fold, P < 0.005), and HC (1.0 ± 0.6-fold, P < 0.005).