Figure 5.

Patients with phenotypic bleeding lack highly contractile platelets associated with clot contraction and force generation. a, Wiskott Aldrich Syndrome and May Hegglin Disorder platelets exhibited significantly reduced contractile forces compared to that of healthy controls (75 kPa gel stiffness, 1U/mL thrombin). In a subset of patients with bleeding diatheses yet normal hemostasis tests, platelet contraction was lower than that of normal healthy controls. b, Histogram data reveal platelet subpopulations of varying contractile forces. Healthy control platelets comprise high contractility subpopulations, notably absent in platelets from a Wiskott Aldrich Syndrome patient. In all panels, n refers to number of platelets, Mann-Whitney statistical test.