Fig. 1.

Platelet abnormalities in patients with Glanzmann thrombasthenia (GT). (A) Flow cytometric analysis of α_IIbβ₃ in platelets of a GT patient carrying the 13-bp deletion in the α_IIb gene, a patient with a −3C → G mutation in intron 14–exon 15 junction of the β₃ gene which causes variant GT, and a healthy control. fluorescein-isothiocyanate (FITC)-conjugated P2 monoclonal antibody against the α_IIbβ₃ complex was used. Background staining with FITC-conjugated mouse IgG is shown in black. (B) Immunoblotting under reduced conditions of sodium dodecyl sulphate-solubilized platelets using polyclonal antibodies against α_IIb and β₃. Notable is the trace amount of pro-α_IIb and β₃ in solubilized platelets of a patient with the 13-bp deletion and the normal amount of α_IIb and β₃ detectable in the patient with the variant mutation. (C) Immunoblot analysis under non-reducing conditions of α_IIbβ₃ immuno-precipitated by 10E5 monoclonal antibody, using SZ22 and AP3 monoclonal antibodies against α_IIb and β₃, respectively. Notable is the absence of α_IIb and β₃ in the patient with 13-bp deletion, and the reduced amounts of α_IIb and β₃ in the patient with the variant mutation compared with control. (D) Fibrinogen binding to resting platelets and platelets activated by 1.25 μm adenosine diphosphate or 1.25 μg mL⁻¹ collagen. Note the impaired binding of fibrinogen to platelets of the patient with the variant mutation compared with control platelets.