An Assay of Measuring Platelet Reactivity Using Monoclonal Antibody against Activated Platelet Glycoprotein IIb/IIIa in Patients Taking Clopidogrel.
10.4070/kcj.2015.45.5.378
- Author:
Seung Jae JOO
1
;
Joon Hyouk CHOI
;
Song Yi KIM
;
Ki Seok KIM
;
Young Ree KIM
;
Sung Ha KANG
Author Information
1. Department of Cardiology, Jeju National University Hospital, Jeju, Korea. sejjoo@jejunu.ac.kr
- Publication Type:Original Article
- Keywords:
Blood platelets;
Glycoprotein IIb/IIIa;
Platelet function test;
Flow cytometry;
Clopidogrel
- MeSH:
Adenosine Diphosphate;
Blood Platelets*;
Coronary Artery Disease;
Flow Cytometry;
Fluorescein;
Fluorescence;
Glycoproteins*;
Humans;
Platelet Function Tests
- From:Korean Circulation Journal
2015;45(5):378-385
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND AND OBJECTIVES: Residual platelet reactivity in patients who are taking clopidogrel is commonly measured with VerifyNow assay, which is based on the principle of light transmission aggregometry. However, to evaluate the residual platelet reactivity, it would be more accurate if the reactivity of platelet glycoprotein (GP) IIb/IIIa is directly monitored. In this study, PAC1, a monoclonal antibody against activated platelet GP IIb/IIIa, was used to measure the residual platelet reactivity. SUBJECTS AND METHODS: Twenty seven patients with coronary artery disease taking clopidogrel were enrolled. Platelets in whole blood were stained with fluorescein isothiocyanate (FITC)-conjugated PAC1. Mean fluorescence intensity (MFI) and % positive platelets (PP) were measured with flow cytometry, and the binding index (BI; MFI x %PP/100) was calculated. P2Y12 reaction unit (PRU) and % inhibition of VerifyNow assay were also measured in the usual manner. RESULTS: PRU of VerifyNow assay correlated significantly with MFI, %PP, and BI at 10 microM (r=0.59, 0.73, and 0.60, respectively, all p<0.005) and 20 microM of adenosine diphosphate (ADP; r=0.61, 0.75, and 0.63, respectively, all p<0.005). The % inhibition also correlated significantly with MFI, %PP, and BI at 10 microM (r=-0.60, -0.69, and -0.59, respectively, all p<0.005) and 20 microM of ADP (r=-0.63, -0.71, and -0.62, respectively, all p<0.005). CONCLUSION: Direct measurements of the reactivity of platelet GP IIb/IIIa were feasible using PAC1 and flow cytometry in patients taking clopidogrel. Further clinical studies are required to determine the cut-off values which would define high residual platelet reactivity in patients on this treatment protocol.
