Similarly, immunodeficient mice adoptively transferred with CD4+IL-21−/− T cells develop less severe colitis [60, 61], and mice treated in a prophylactic setup with a neutralizing IL-21R/Fc fusion protein or anti-IL-21 mAb are protected from both DSS and TNBS-induced colitis [31, 58, 59]. This evidence concerns the gene CD4 and colitis.