Recombinant human GPIbα blocks platelet response to S100A8/A9, whereas Bernard-Soulier syndrome platelets failed to respond to S100A8/A9. Washed human platelets (106 platelets/condition) were incubated with S100A8/A9 (40 μg/mL) in the absence or presence of recombinant human GPIbα (rGPIbα; 1.7 μM) for 30 minutes at 37°C (n = 3). Platelet activation was assessed by flow cytometry using (A-C) anti–P-selectin, (D-F) PS exposure using annexin-V, and (G-I) GPIIb/IIIa activation using PAC-1 antibody. Human washed platelets from a healthy donor or a Bernard-Soulier syndrome patient were incubated with S100A8/A9 (20 and 40 μg/mL) for 30 minutes at 37°C (J-L). CRP (10 μg/mL) was used as positive control. (J) GPIIb/IIIa activation, (K) P-selectin, and (L) PS exposure were measured. The statistical significance was analyzed using one-way ANOVA. Data presented as mean ± SEM. ∗P < .05, ∗∗P < .005, ∗∗∗P < .001, ∗∗∗∗P < .0001.
