Effect of DDAVP on platelet surface glycoproteins, dense-granule content, agonist-induced α-granule secretion, and GPIIb-IIIa activation. Whole blood was drawn before and at 2 and 4 hours after start of the DDAVP infusion in 16 patients with congenital platelet function defects (results at 2 and 4 hours after DDAVP were similar and were therefore pooled). (A) Surface density of GPIIb (CD41; Wilcoxon signed rank test P = .006; n = 16), GPIIIa (CD61; P = .044), and GPIb (CD42b; P = .323). (B) Dense-granule content (P = .322) and their thrombin-induced secretion (P = .462). (C) Secretion of α-granules induced by ADP (P < .001), thrombin (P < .001), and convulxin (P = .019). (D) Activation of GPIIb-IIIa induced by ADP (P < .001), thrombin (P = .004), and convulxin (P = .080). Box plots visualize the median value (horizontal line within the box), the 25th and 75th percentiles (lower and upper borders of the box), the 10th and 90th percentiles (lower and upper whiskers), and each outlier outside the 10th and 90th percentiles (black circles).