STAT1 and Autoimmunity: Th1 stimulation renders the Stat1 promoter to undergo a DNA methylation turnover featured by the changes of DNA methylation levels or patterns along with the induction of MBD2 expression, which then binds to the methylated CpG DNA within the Stat1 promoter, by which MBD2 maintains the homeostasis of Th1 program to prevent autoimmunity.