Clinical studies have shown that many immune-related diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis, polymyositis/dermatomyositis, Sjögren’s syndrome, Treg cell defects, and Th17/Treg cell imbalance, may benefit from low-dose IL-2 treatment [24–28]. The gene discussed is IL2; the disease is rheumatoid arthritis.