It is documented that not all CpG’s in regulatory regions have the same methylation level in different donors [i.e. neonatal and adult T-cells differ in IFNG gene promoter particular CpG’s methylation pattern (32)], or in normal and affected conditions [i.e. the upstream CpGs at -408, -387, -385, and -355 bp had similar hypermethylated status in both the patients with rheumatoid arthritis and healthy donors, whereas the proximal CpG at -145 was hypomethylated to a much greater extent in the patients than in the controls (37)]. Here, IFNG is linked to rheumatoid arthritis.