The use of fluorescence flow cytometry in the characterization of Bernard-Soulier syndrome and Glanzmann's thromboasthenia

We have used flow cytometry analysis of fluorescence to study the binding of murine monoclonal antibodies to platelets. Anti-platelet glycoproteins Ib (AP1), the complex IIb-IIIa (LJP9) and the FITC-conjugated second antibody were added directly to the sample of platelet rich plasma without washing. The analysis was performed in normals and in patients affected by the Bernard-Soulier syndrome and Glanzmann's thrombasthenia and compared to the direct binding of radioiodinated monoclonas. Comparable results were obtained. A symmetric profile of fluorescence for both glycoproteins Ib and IIb-IIIa was observed in normals and in the patient group, which indicates homogeneous distribution of these glycoproteins on the platelet surface. The develop technique allows identification of homozygous and heterozygous carriers of the platelet disorders studied and quantification of the defect, which seems to be due to a homogeneous decrease of specific glycoproteins in all platelet populations.