Our results showed that the relative mRNA levels of TLR4 (26.28 ± 6.41, P < 0.001) and its downstream factors MyD88 (23.43 ± 3.33, P < 0.001) and NF-κB (4.67 ± 1.24, P < 0.001) were significantly upregulated in PM patients compared to those of their respective controls (4.97 ± 2.59, 4.99 ± 2.50, and 0.94 ± 0.23) (Figure 2A). This evidence concerns the gene MYD88 and polymyositis.