These cells suppress autoreactive T lymphocytes and require IL-2 for their proper development and homeostasis, which is why alterations in this gene are correlated with immunodeficiency [47] or the development of autoimmune diseases such as type-1 diabetes mellitus, multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis and celiac disease [5, 48–50]. The gene discussed is IL2; the disease is autoimmune disease.