VWF/platelet complexes circulate in the blood of VWD type 2B mice. Blood smears prepared with blood collected from mice expressing either wt-mVWF (A), p.R1306Q-mVWF (B-C), or p.V1316M-mVWF (D). Mice had normal or slightly low platelet counts (A-B) or were thrombocytopenic (C-D). Platelets were detected by staining for the CD41 surface marker (red), and VWF (green) was detected with primary rabbit anti-human VWF antibody followed by a secondary AlexaFluor 488–goat anti-rabbit antibody. Original magnification is ×100. (A-B) Single platelets can be observed, and no VWF at the platelet surface could be detected. (C-D) Thrombocytopenic mice display circulating single platelets and platelet aggregates, both of which are characterized by the presence of VWF at the platelet surface.