ADAMTS13 proteolysis of ABO-matched Y/Y1584 and Y/C1584 VWF. (A) Y/Y1584 VWF (n = 50) and Y/C1584 VWF (n = 50) were randomly divided into 8 sets. Proteolysis was then measured for each set (“Analysis Number”). Data points for Y/C1584 VWF are boxed, whereas those for Y/Y1584 VWF are not. The mean for Y/C data points is above the box, and the mean for Y/Y data points is below the data points. Within each analysis, no overlap occurred in proteolysis between Y/Y1584 VWF and Y/C1584 VWF. (B) Proteolysis data for the 8 sets of analyses in panel A were combined to allow inspection of the effect of ABO blood group. Proteolysis of group O and group A VWF was not statistically different for Y/Y1584 and Y/C1584 phenotypes together or individually, but it was marginally higher for group O in each comparison, and this approached significance for Y/Y1584 VWF. In both panels, proteolysis is measured as the percentage of loss in VWF:CB.