IIbβ3 expression in platelets from patients GW, JF, and Chinese-14.

(A) Flow cytometric analysis of platelets from patient GW (solid bars) and a patient with a known deficiency of surface αIIbβ3 receptors (FLD)14 (shaded bars). Data are expressed relative to a concurrently studied normal control (100%), whose platelets are known to express normal amounts of αIIbβ3.14,26 Measurements of the binding of the β3-specific monoclonal antibody SSA6, the αIIb-specific monoclonal antibody B1B5, the αIIbβ3-specific monoclonal antibody A2A9, and the GPIb-specific monoclonal antibody AP1 were performed with the use of unstimulated platelets. PAC1 binding was measured after stimulating platelets with the phorbol myristate acetate. (B) Immunoblots of separated proteins from the platelets of patients JF and Chinese-14 and a normal control (labeled C) were performed with the use of the anti-αIIb heavy-chain–specific monoclonal antibody PMI-1 and the anti-β3–specific monoclonal antibody 7H2. Identical amounts of platelet protein from each subject were immunoblotted.