CD8A and neoplasm: There are key factors that are involved in Th2-mediated immunity that can play a pro-tumoural role, such as eosinophils (IL-10 inhibits tumour cell lysis by CTLs); IL-13 (NKT-cell-derived IL-13 inhibits CTL activation); Type 2 CD8+ T cells (Tc2 cells by IL-10 secretion); B cells (inhibit CTL-mediated tumour clearance by IL-10 secretion and formation of immune complexes) [435].