The impact of the Gly233Val mutation on platelet attachment and translocation velocities. (A) Platelets (5 × 107/mL) purified from 2 patients with PT-VWD or 5 healthy individuals were infused at the indicated wall shear rates through a parallel plate flow chamber apparatus for 5 minutes. The total number of healthy platelets attached to either surface-immobilized plasma VWF (25 μg/mL) or recombinant VWF-A1 protein (100 μg/mL) was determined and compared with PT-VWD platelet interactions with VWF-A1 (mean ± SD; n = 5). The specificity of the interaction was determined by the ability of the GPIbα-blocking antibody, mAb 6D1, to inhibit healthy platelet or PT-VWD platelet (not shown) to A1 substrate. (B) Mean translocation velocities for healthy or PT-VWD platelets (n = 30 to 40 cells) interacting with the immobilized VWF-A1 substrate were determined at the indicated wall shear stresses. Data represent the mean ± SD for 3 to 4 independent experiments performed in duplicate.
