CD4 and neoplasm: However, it is also required for survival, function, homeostasis, and differentiation of effector T cells including CD4+ Th cells and invariant NK T cells,516,517 and increased PD-L1 expression is induced by PRMT5 inhibition in tumor cells.518,519 Accordingly, genetic or pharmacological targeting of PRMT5 compromises T cell-mediated antitumor immunity.