Among the 47 CpG sites in the nine IFN-related genes, 41 CpG sites exhibited decreased methylation (hypomethylation) in SLE patients compared with NC on mean β value (p < 0.05), including two sites on four genes (IFI35, IFITM2, IFIT1 and OAS1), three on IFIT3, five on IFITM3, six sites on STAT1, eight sites on IFNGR2 and 11 sites on MX1 (Fig. 4d). This evidence concerns the gene OAS1 and systemic lupus erythematosus.