DNMT1 and autoimmune disease: However, owing to the high heterogeneity of autoimmune diseases and complexity of epigenetic mechanisms involved, some studies have shown that the DNMT inhibitor 5’-aza-2’-deoxycytidine can promote the expression of Foxp3 in Treg cells to a certain extent, thus strengthening its immunosuppressive function; however, the continuous use of inhibitors can lead to a decrease in DNMT1 activity, which will instead disrupt the function of Tregs and induce fatal autoimmunity in mice (230).