Reduced PNA binding to post-DDAVP VWF. For a selection (n = 11) of the VWD type 1 patients (Figure 4) as well as VWD type 2A (n = 2), VWD type 2N (n = 1), hemophilia A (n = 1), and storage-pool disease (n = 3) patients, VWF antigen levels (A) and PNA binding (B) were determined in plasma samples that were taken prior or 60 minutes after DDAVP treatment. Mean VWF levels were 0.62 ± 0.46 U/mL and 1.55 ± 0.74 U/mL before and after DDAVP, respectively (P = .001). Mean PNA binding was 131% ± 45% and 85% ± 33% (P = .001). For 2 patients, changes in VWF antigen levels (C-D: right axes) and PNA binding (C-D: left axes) were followed in time.