These results suggest that interactions between the PD-L1 and PD-L2 ligands expressed on EBV-infected lymphoma cells and the PD-1 receptor expressed on T cells might inhibit the ability of T cells to control the growth of EBV-infected lymphoma cells in this model, and that blockade of this interaction with PD-1 blocking antibody might thus improve the ability of cord blood T cells to inhibit lymphoma growth. This evidence concerns the gene PDCD1 and lymphoma.