Fig 1: Surface values of immune checkpoints on exosomes isolated from plasma of HNSCC patients.Exosomes from n = 17 HNSCC patients obtained at defined time-points were captured using biotinylated CD63-antibodies and stained with fluorochrome-conjugated antibodies against PD-L1 (a), CTLA-4 (b), OX40 (c) and OX40-L (d). 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. Wilcoxon related samples tests were applied to each compare pre-OP, post-OP, end (C)RT and follow-up. Mann–Whitney test was applied to compare recurrence with follow-up. * or # and ** or ## correspond to p = 0.05 and p = 0.01, respectively. Asterisks and values above boxes indicate the significance compared to pre-OP. Hashtags above boxes indicate the significance compared to follow-up. c RT (chemo)radiotherapy