The use of CDK8/19 small molecule inhibitors such as CCT251921 or Senexin A to inhibit the activity of CDK8/19 greatly promotes the differentiation of Treg cells and the expression of Treg characteristic genes Foxp3, CTLA4, PD-1, and GITR. In an experimental autoimmune encephalomyelitis (EAE) model, treatment with CCT251921 significantly increased the population of Treg cells and improved autoimmune symptoms (Guo et al., 2019). This evidence concerns the gene CDK8 and experimental autoimmune encephalomyelitis.