On the other hand, we noticed another set of IFN-inducible genes, PAPP9, MX1, IFI44L, and PLSCR1, which were significantly hypomethylated but no difference on the gene expression level in SSc compared with NC, suggesting the overexpression of IFN-inducible gene was not directly regulated by DNA methylation in PBMC of SSc. Here, MX1 is linked to systemic sclerosis.