PDCD1 and neoplasm: Our finding that PD-1/CTLA-4 blockade in this model greatly enhances the ability of T cells to produce the anti-tumor cytokine IFN-γ in response to EBV peptides confirms and extends a recent in vitro study showing that PD-1 blockade increases the ability of co-cultured T cells to proliferate in the presence of EBV-positive DLBCLs [23].