Fig. 3: PD-L1 on exosomes isolated from plasma of HNSCC patients.

a Exosomes from n = 12 successfully treated and n = 5 recurrent HNSCC patients were captured using biotinylated CD63-antibodies and stained with fluorochrome-conjugated antibodies against PD-L1. Surface values as determined by on-bead flow cytometry are shown as RFI compared to an appropriate isotype control. Results are plotted as box-and-whisker blots representing the median value, the 25th and 75th quartiles and the range. P-values were determined by Mann–Whitney test, with * corresponding to p ≤ 0.05. b Kaplan–Meier curves with log-rank test for disease-free survival (DFS) of n = 17 HNSCC patients grouped according their exosomal PD-L1 (exoPD-L1) values. ExoPD-L1 status was determined at different time-points using the median as cut-off. Solid line indicates high exoPD-L1 and dashed line low exoPD-L1.