Adoptive transfer colitis, firstly conceived by Powrie [19] and based on the injection of CD45Rbhigh subset of CD4+ T cells to syngeneic immunodeficient, SCID or Rag1−/−, mice, has become a predictive model of chronic colitis ensuing from the perturbation of intestinal immune homeostasis, and is considered similar to CD in terms of histopathology and gene expression patterns [20]. Here, CD4 is linked to colitis.