Platelets from FHL5/Munc18b/STXBP2 patients have a defect in ADP/ATP release and P-selectin exposure. Washed platelets were stimulated with thrombin (0.1 U/mL), and the release of ADP/ATP from dense granules was measured in a lumi-aggregometer as described previously.34 (A) ATP release profile from a normal control (black line) and biallelic patient 1 (gray line). (B) Release profiles for a normal control (black line) and a heterozygous patient 3 (gray line). (C) Resting (black line) thrombin-stimulated (gray line) platelets from control, or biallelic, patient 1 were incubated with FITC-conjugated anti–P-selectin antibodies for 1 minute at room temperature. The reactions were stopped with hirudin, and the stained platelets were analyzed by flow cytometry. A similar experiment was repeated with PAC-1 antibodies (D).
