Evaluation of an antibody-based genotype classification of the platelet fibrinogen receptor (GPIIb/IIIa)

Platelet membrane glycoprotein (GP) IIb/IIIa is the central molecule in pla telet adhesion and aggregation by high-affinity binding of fibrinogen. Poly morphism of the beta chain of the receptor, especially the GPIIIa-proline33 allele [HPA-1b, Zwb, PI(A2)], has been suggested to be associated with a v ariety of vascular diseases, such as coronary stenosis, myocardial infarcti on, cerebral ischemia, or venous thrombosis. Using clinical chemistry stand ards, we evaluate a flow cytometric whole-blood, antibody-based method to d etermine the genotype EPI(A1A1), PI(A1A2), PI(A2A)] versus polymerase chain reaction (PCR)based DNA restriction fragment length analysis in 220 indivi duals. Both homozygous and heterozygous genotypes differ in the expression of binding sites for the monoclonal antibody, SZ21. Agreement between the t wo methods was achieved in 187 cases, which reflects a test validity of 85% , a sensitivity of 83.6%, and a specificity of 85.4%. We conclude that flow cytometry is reliable for classifying the PI(AX) genotype. The performance characteristics are easy, fast, and cheap (genomics by proteomics). These features make it suitable for screening patients and broad populations for the future risk of cardiovascular ischemic events. (C) 2001 Wiley-Liss, Inc .