CD4 and colonic neoplasm: To further investigate the source of IL-17A, we compared the proportions of CD8 + T cells, CD4 + T cells and γδTCR + T cells in CD3 + T cells in colon tumours, and the results showed that the proportion of γδTCR + T cells in IL17A + /CD3 + T cells was significantly increased compared to that in CD3 + T cells, while the proportions of CD8 + T cells and CD4 + T cells did not change (Fig. 7D).