Fig. 4: Nucleoside production of exosomes and CD4⁺ CD39⁺ T cells co-cultured with exosomes.

5’-AMP, adenosine and hypoxanthine levels were measured by mass spectrometry upon incubating exosomes alone (a) or exosomes plus CD4⁺ CD39⁺ T cells (b) with exogenous ATP. ATP only (a) and CD4⁺ CD39⁺ T cells with ATP (b) were included as controls. All results are plotted as box-and-whisker blots representing the median value, the 25th and 75th quartiles and the range from n = 6 replicates (controls), n = 10 (pre-OP), n = 5 (post-OP, non-recurrence, recurrence) HNSCC patients. All p-values were determined by Mann–Whitney test, with *, ** and *** corresponding to p ≤ 0.05, p ≤ 0.01 and p ≤ 0.0001, respectively. Asterisks above or below boxes indicate the significance compared to the control.