Fig. 2: PD-1 NK cells express lower levels of activating receptors and reduced functionality, which can be partially reversed.

A The percentages of PD-1^pos NK cells were compared between the CD56^bri and CD56^dim NK populations. B Dot plots to compare the percentages of CD57^pos and NKG2A^pos NK cells between PD-1^pos NK cells (red circles) and PD-1^neg NK cells (blue squares). C Dot plots to compare the percentages of DNAM-1^pos, NKp30^pos, NKp46^pos, and NKG2D^pos NK cells between PD-1^pos NK cells (red circles) and PD-1^neg NK cells (blue squares). Statistical significance was determined by Wilcoxon matched-paired nonparametric test using GraphPad Prism (*p < 0.05, **p < 0.01, ***p < 0.001). D Bar charts summarizing IFN-γ and TNF-α production by PD-1^pos (red circles) vs. PD-1^neg (blue squares) NK cells from B-CLL patients after stimulation with 721.221 (n = 10). E Bar charts summarizing IFN-γ production by PD-1^pos NK cells (red) and PD-1^neg NK cells (blue) before and after PDL-1/L-2 blockade. Each dot represents a single donor. The differences were determined by the Mann-Whitney test using GraphPad Prism (*p < 0.05, **p < 0.01). F Bar chart to compare CD107a expression after stimulation with 721.221 by PD-1^pos NK cells (red) and PD-1^neg NK cells (blue) before and after PDL-1/L-2 blockade. Data are shown as the percentage of CD107a-expressing NK cell subsets (n = 10). G Summary of CD107a expression in PD-1^pos NK-92 (white bars) and PD-1^neg NK-92 (black bars) cells after stimulation with 721.221 before and after PDL-1/L-2 blockade. H Bar charts to compare the cytotoxicity capacity of PD-1^pos NK-92 (white bars) and PD-1^neg NK-92 (black bars) against 721.221 target cells with and without PDL-1/L-2 blockade. Data were analyzed using Mann-Whitney and Wilcoxon matched-paired nonparametric tests (*p < 0.05, **p < 0.01, ***p < 0.001).