Sickle RBC adhesion to mixtures of TSP and vWF. TSP and vWF were combined in solution at various ratios and coated onto glass microscope slides. Sickle RBC adhesion was assessed as in Fig 1. In combination with a fixed concentration of TSP (50 μg/mL), vWF exerted a concentration-dependent inhibitory effect. The effects of both recombinant and plasma vWF are shown in (A) and (B), respectively. Indicated weights represent total amounts of protein present in the mixture. Error bars are SEM.