CD4 and rheumatoid arthritis: These studies demonstrated the following: significant changes in methylome of CD4 + memory cells compared to CD4 + naïve cells [84]; specific methylation-induced regulation of CTLA4 promoter [85] and FOXP3 enhancer in Tregs [86]; evidence for epigenetic regulation of inflammatory cytokines in monocytes [87]; and multiple immune-related pathways in fibroblast-like synoviocytes (latterly, in comparison with osteoarthritis) [88] in RA.