546 The differentiation status of systemic PD1+ CD8 T cells is associated with favorable outcome to PD1 blockade therapy in non small cell lung cancer
BackgroundNon small cell lung cancer is one of the cancer types where Immune checkpoint blockade has demonstrated unprecedented clinical efficiency. However, only a fraction of patients benefit from such therapy; factors determining this response are yet to be elucidated. Here, we investigated whether the differentiation status of circulating CD8 T cells might be associated with outcome of PD1 blockade therapy in NSCLC.MethodsWe used multi-parameter flow cytometry to study CD8 T cell differentiation states in NSCLC patients at baseline and to examine the effects of blocking the PD1/PDL1 pathway on those cells.ResultsWe found that responders to PD1 blockade therapy has more peripheral PD1+ CD8 T cells with an early-like differentiated status at baseline and that this phenotype is associated with longer survival. Moreover, PD1 blockade induced reinvigoration is mostly observed in cells with this with an early-like differentiated status.ConclusionsAn early like differentiation status of peripheral CD8 T cells is associated with favorable outcome of PD1 blockade immunotherapy