CD4 and colitis: Further, a significantly increased frequency of CD4+, CD8+ T, CD4+ IFN-γ+ Th1, and CD4+ IL17+ Th17 cells, but decreased Tregs, were detected in the colon mucosal LP of the colitis group (Figures 4(a)–4(e)), indicating that CD4+, CD8+, Th1, and Th17 cells infiltrate into the LP of the colon during the process of chronic colitis.