CD69 and colitis: Notably, the numbers of CD4+CD69+CD103− and CD4+CD69+CD103+ TRM cells were strongly increased in DSS-induced mice when compared to control mice, although the percentages of CD69+CD103− and CD69+CD103+ TRM cells within CD4+ T cell were similar (Figures 1E–G) indicating that circulating CD4+ T cells could differentiate into TRM cells and take residency in the gut during the induction of colitis.