In another study, S100A6 and EFCAB4B promoter regions in the whole blood and IFN-related genes (IFIT1, IRF7, MX1, OAS1, USP18, RSAD2, IFI44L) in CD4+ T cells are hypomethylated, indicating these methylation signals might be used as biomarkers for RA diagnosis (Svendsen et al., 2016; Chen et al., 2019). Here, OAS1 is linked to rheumatoid arthritis.