The Slc44a2/HNA-3a epitope is necessary for cell slow rolling to VWF under flow. (A,C) Compiled amount of HEK293T cells (n = 5 independent experiments) (A) or neutrophils (HNA-3a, n = 6 donors; HNA-3b, n = 3 donors) (C) counted in function of their mean velocity (µm/s) on coated VWF when submitted to a 100 s⁻¹ shear rate. The dashed line separates sedimented (left) from nonsedimented cells (right). Red, HNA-3a–expressing cells; blue, HNA-3b–expressing cells. (B,D-E) Graphs depicting the slow-rolling and rolling profiles of HEK293T cells (B) and neutrophils (D-E) perfused on a VWF matrix under flow at a 100 s⁻¹ shear rate. Perfusion of cells at 100 s⁻¹ resulted in more slow rolling of Slc44a2/HNA-3a–expressing HEK293T cells (B; n = 5 independent experiments) and neutrophils (D; HNA-3a n = 6 donors; HNA-3b n = 3 donors) to human VWF-coated channels compared with Slc44a2/HNA-3b–expressing cells (blue). Slow rolling of Slc44a2/HNA-3a expressing neutrophils (E, n = 7 donors) to VWF were blocked by VWF-A1 domain–blocking monoclonal antibody (control IgG, light green; anti-VWF-A1-IgG, purple). Data are represented in nested form, and values obtained for each field are shown. Three fields were analyzed for each experiment/donor. (A,C) Mean ± SEM; (B-D) nested t test, minimum/maximum, quartiles, and medians are represented. *P < .05; **P < .01; ***P < .005.