Targeting immune checkpoints in lymphoma

The purpose of this article is to discuss the tumor microenvironment in lymphoma, and to review potential immune targets that are now becoming relevant because of clinical responses seen with the use of immune checkpoint inhibitors.Recent data have shown that cells within the immune microenvironment in lymphoma express programmed death ligand-1 (PD-L1) and many of the intratumoral T cells with an exhausted immune phenotype express programmed cell death-1 (PD-1). This provides a novel opportunity to inhibit the immune checkpoints and initial clinical trials utilizing antibodies that block the interaction between PD-1 and PD-L1 have demonstrated significant clinical responses in various lymphomas, including Hodgkin lymphoma.The use of immune checkpoint inhibitors, including nivolumab and pembrolizumab, in relapsed and refractory patients with lymphoma is proving highly successful. Patients with Hodgkin lymphoma, in particular, have a very high response rate to PD-1 blockade and responses in these patients appear durable.