Purpose of the review: The ligation of PD-1 with PD-L1 activates a critical immune checkpoint leading to T cell dysfunction, exhaustion, and tolerance. Anti-PD-1 or anti-PD-L1 monoclonal antibodies can reverse the immune checkpoint, releasing the brake on T cell responses. We provide a comprehensive review of the literature on the activity of checkpoint inhibitors in lymphoma.
Recent findings: We discuss the latest findings with checkpoint inhibitors in lymphoma and new promising studies incorporating these agents. Classical Hodgkin lymphoma is very sensitive to PD1/PL1 blockade due to genetic alterations in 9p21.1 leading to the high expression of PDL1. Although majority of NHLs have a much lower sensitivity to PD1/PDL1 blockade, a few subtypes such as primary CNS lymphoma, primary testicular lymphoma, primary mediastinal lymphoma harbor 9p21.1 alterations making them vulnerable to PD1 blockade. EBV-associated lymphomas have a virally mediated increased expression of PDL1 making them sensitive to PD1 blockade.
Keywords: Checkpoint blockade; Hodgkin lymphoma; Immunotherapy; Nivolumab; Non-Hodgkin lymphoma; PD-1; PD-L1; Pembrolizumab.