Naturally occurring tumour‐specific HLA‐II‐restricted CD4+ T cells and those engineered to express HLA‐I‐restricted tumour TCRs have been reported to exhibit a mainly Th1 phenotype, where cells typically produce IFN‐γ, TNF‐α and IL‐2 but not IL‐4, IL‐5 or IL‐10 [13–15,21]. Here, IL5 is linked to neoplasm.