CD4 and colitis: This could be confirmed by histological analysis, which revealed larger inflammatory infiltration of lymphocytes in H&E staining and the accompanying inflammation score (Figure 2C) due to the transfer of Arl4d+/+ CD4 T cells compared to Arl4d−/− CD4 T cells, indicating that the expression of Arl4d in CD4 T cells augments colitis severity.