The role of TH1 and TH17 cells in inflammatory disease is reflected by the induction of colitis upon adoptive transfer of naïve CD4+ T cells into Rag2–/– mice, which is marked by a wasting phenotype, inflamed colon, splenomegaly, and a TH1/TH17 hybrid‐driven inflammatory response [27]. The gene discussed is CD4; the disease is colitis.