CD4 and lymphoma: Besides Th1 and Th2, in addition Th0, Th17, Th9 and Th22 cells and other potentially relevant Th phenotypes could contribute to the overall Th infiltration of BL, such as bcl‐6+ and/or c‐Maf+ T follicular helper cells, which are variably represented among CD4+ T cells in lymphomas of the GC phenotype, or variants in regulatory subsets that may be aberrantly expanded in tumours, such as eomesodermin+/granzyme K+/type 1 regulatory‐like CD4+ effectors.32