[Membrane glycoproteins of human platelets: structures, functions, and abnormalities in Glanzmann's thrombasthenia and Bernard-Soulier syndrome].

Platelet membrane glycoproteins, especially those of GP II b-III a complex and GP Ib-IX complex, serve as receptors for adhesive proteins including fibrinogen, von Willebrand factor and fibronectin, thus supporting cell-cell and cell-matrix interactions. Thrombasthenia (TA) and Bernard-Soulier syndrome (BSS) are inherited bleeding disorders in which these membrane glycoprotein complexes are defective. This paper deals with the recent advances in platelet membrane glycoprotein research, and the membrane glycoprotein abnormalities in TA and BSS platelets, which have been disclosed by the development of improved methods of analysis. Furthermore, a case of TA is reported in which flow cytometry using murine monoclonal antibody revealed 18% of the normal level of GP II b-III a complexes in her platelets. The platelets of this patient aggregated well by the addition of high concentrations of collagen (40 micrograms/ml). The results of this patient show the necessity of new criteria for the diagnosis of TA based on the quantification of the residual contents of GP II b-III a complexes in platelets in each patient.