For treatment of several autoimmune disorders such as type 1 diabetes, HCV-induced vasculitis and graft vs. host disease (GVHD), IL-2 is administered at low doses and has been beneficial for patients because it targets the constitutive expression of the high affinity IL-2R leading to selective proliferation of Tregs (201–204). This evidence concerns the gene IL2RA and graft versus host disease.