These results are consistent with previous studies showing that newly expanded T-cell clones correlated with severe IrAEs from CTLA4-blockade (18, 22, 23) This study included two patients who experienced severe colitis under CTLA4 blockade (black dot, Figure 5) and had the most prominent increases in CD4+ T-cell repertoire restrictions (black dot, Figure 5). This evidence concerns the gene CTLA4 and colitis.