ICOS and colitis: Compared with the normal group, the numbers of CD4+CXCR5+BCL-6+ (Figures 4A–C), CD4+CXCR5+ICOS+ (Figures 3A,B,F), CD4+CXCR5+PD-1+ (Figures 4A,B,E), and CD4+CXCR5+PD-L1+ (Figures 4A,B,F) T cells were significantly elevated, while CD4+CXCR5+Blimp-1+ T cells (Figures 4A,B,D) were inhibited in the peripheral blood of colitis mice in the DSS group.