PD-L1

Q: 48 years old male with a history of laryngeal cancer is admitted to ICU for airway monitoring due to stridor and hemoptysis. Oncology service ordered Programmed death-ligand 1 (PD-L1). What is its utility?

Answer: The objective of this question is to introduce ICU care providers with fastly rising immuno-therapy in the oncology field. Cancer patients requiring immunotherapy are now frequently getting admitted to ICU. Programmed death ligand 1 (PD-L1) and its partner PD-L2 is a transmembrane protein expressed in normal tissues to inhibit the activity of T-cells and prevent autoimmunity. PD-L1 is commonly upregulated on the surface of tumor cells, binding to the programmed death 1 (PD-1) expressed on tumor-infiltrating lymphocytes, eventually causing a T-cell tolerance. 

This represents one of the various mechanisms of immune evasion. PD-1 inhibitors (nivolumab and pembrolizumab) exploit this immune escape and are now used for various cancers including head, neck, lungs, and gastroenterology cancers.

#oncology


References: 

Inaguma S, Wang Z, Lasota J, et al. Comprehensive Immunohistochemical Study of Programmed Cell Death Ligand 1 (PD-L1): Analysis in 5536 Cases Revealed Consistent Expression in Trophoblastic Tumors. Am J Surg Pathol. 2016;40(8):1133-1142. doi:10.1097/PAS.0000000000000653