While in normal conditions, Treg cells are prevalent in the intestine to guarantee a tolerance state, in patients with IBD, Th1 and Th17 become predominant, resulting in increased production of interferon (IFN)-γ and inflammatory interleukins (ILs), such as IL-23 and IL-12 by the Th1 subset, and IL-17 by the Th17 subset [21]. The gene discussed is IL17A; the disease is inflammatory bowel disease.