Programmed death ligand 1 (PD-L1) expression influences the immune-tolerogenic microenvironment in antiretroviral therapy-refractory Kaposi's sarcoma: A pilot study

Oncoimmunology. 2017 Apr 7;6(8):e1304337. doi: 10.1080/2162402X.2017.1304337. eCollection 2017.


Upregulation of programmed death ligand 1 (PD-L1) is a mechanism of immune escape utilized by a variety of tumors. PD-L1 expression in tumor cells or in the surrounding infiltrate correlates with clinical responsiveness to novel therapies targeting the PD-1/PD-L1 immune checkpoint. In the context of HIV-1 infection, Kaposi's sarcoma (KS) is largely responsive to restoration of immunity following combination antiretroviral therapy (cART), but there is a subset that is not. We hypothesized that this subset of cART-refractory KS may utilize the PD-L1 pathway of immune escape. We found that PD-L1 expressing KS had a denser CD8+ T cell (p = 0.03) and PD-L1 positive macrophage peritumoral infiltrate (p = 0.04) to suggest the involvement of PD-L1 in shaping an immune-tolerogenic microenvironment in cART-refractory KS. The presence of PD-L1 expression in association with immune-infiltrating cells provides rationale for the clinical development PD-1/PD-L1-targeted checkpoint inhibitors in cART-refractory KS.

Keywords: HIV; KS; PD-L1; cART; microenvironment.

Publication types

  • Research Support, Non-U.S. Gov't