Monocyte and neutrophil surface activation marker expression is suppressed after incubation with GPA-overexpressing TF-1 cells in a contact- and dose-dependent manner. The relative median fluorescence intensities (rMFIs) of monocyte CD63 (n = 4) (A) and neutrophil CD66b (B) (n = 3) were measured for isolated activated leukocytes from healthy donors alone (blue), or coincubated with GPA Overexpressing TF-1 cells at either a 100:1 ratio (red), or at a 200:1 ratio (green), and incubated with GPA Overexpression TF-1 cells (200:1) separated by a transwell insert (yellow). rMFI of monocyte CD63 (C) and neutrophil CD66b (D) for isolated leukocytes alone (red) or after incubation with healthy RBC-derived GPA-microvesicles at 20 000:1 ratio (dark blue), with leukocytes in whole blood serving as a negative control baseline (light blue). A one-way ANOVA test with Bonferroni post hoc was performed. ∗ P < .05; ∗∗ P < .01; ∗∗∗∗ P < .0001; ns P > .05.