Immune Cell PD-L1 Colocalizes with Macrophages and Is Associated with Outcome in PD-1 Pathway Blockade Therapy

Abstract

In nearly 500 non-small cell lung cancer (NSCLC) cases, the predominant immune cell type that expresses PD-L1 is CD68⁺ macrophages. The level of PD-L1 in macrophages is significantly associated with the level of PD-L1 in tumor cells and infiltration by CD8⁺ T cells, suggesting a connection between high PD-L1 and "hot" tumors. In anti-PD-1 axis therapy-treated patients, high levels of PD-L1 expression in macrophages are associated with longer OS and may be responsible for the predictive effect of the marker.