In this study, CD4+CCR7+/− cells in mice with DSS-induced colitis were overactivated, and their subsets CD4+CCR7+IL-17A+ and CD4+CCR7−IL-17A+ increased significantly, while CD4+CCR7+IL-10+, CD4+CCR7−IL-10+, CD4+CCR7+Foxp3+, and CD4+CCR7−Foxp3+ decreased significantly. Here, IL17A is linked to colitis.