Fig. 3: Platelets from NSCLC patients show increased PD-L1 levels.

a Left panel, left, Immunohistochemistry for CD61 in healthy human lung tissue (black arrow highlights CD61+ platelets). Scale bar 200 µm. Left panel, right, Representative micrograph of healthy lung tissue (H&E). Scale bar 500 µm. Right panel, Immunofluorescence microscopy for CD41+ (green), PD-L1- (red) platelets in healthy lung tissue (n = 3). Scale bar left 100 µm, right 10 µm. b Immunofluorescence staining for CD41 (green) and PD-L1 (red) on platelets in a PD-L1− NSCLC patient tumor sample (n = 3). Scale bar left 500 µm, center left 50 µm, center right and right 10 µm. c Upper, Representative micrographs of NSCLC adenocarcinoma (H&E) (n = 3). Scale bar left 250 µm, center 50 µm, right 500 µm. Lower, Immunofluorescence staining for CD41 (green) and PD-L1 (red) (n = 3). Scale bar left 500 µm, center left 50 µm, center right and right 10 µm. d, e Quantitative analysis of the platelets/FoV (d) and PD-L1+ platelets (%/FoV) (e) in healthy lung tissue, PD-L1+ and PD-L1- NSCLC patients (n = 9) (small symbols) were analyzed out of three independent experiments in three healthy donors and six NSCLC patients (large symbols). Horizontal line represent mean. f Percentage of PD-L1+ platelets in healthy donors (n = 64) and NSCLC patients (n = 128). Each dot represents a single donor. Boxes represent median and 25th to 75th percentiles, whiskers are minimum to maximum. g Total amount of PD-L1 (pg/mL) in healthy donors (n = 21) and NSCLC patients (n = 64) analyzed by ELISA. Protein level were analyzed in 64 out of 128, randomly assigned patients of the NSCLC cohort. Data are mean ± SEM. h Total amount of PD-L1 (pg/mL) in PRP, platelet lysate, platelet releasate, and serum (n = 6). Data are mean ± SEM i Left, Representative PD-L1 immunofluorescence staining of platelets from a healthy donor (upper) and a NSCLC patient (lower). Platelets were counter stained with phalloidin. Right, Expression pattern of PD-L1 on a platelet derived from a NSCLC patient counter stained with phalloidin (upper) or CD41 (lower). Scale bar left 10 µm, right 2 µm (n = 1). j Platelets of a NSCLC patient, assessed by transmission electron microscopy. PD-L1 stained with post-embedding immunogold-labeling. PD-L1 gold particles densely accumulating on the platelet membrane (black dots). Upper scale bar 2 µm, lower 100 nm (n = 1). d, e, h Statistical significance was calculated by one-way ANOVA and Tukey’s multiple comparisons test. f, g Statistical significance was calculated by Mann–Whitney test. Source data are provided as a Source Data file.