Expression of markers of platelet activation and the interpatient variation in response to abciximab

Arterioscler Thromb Vasc Biol. 1999 Feb;19(2):212-9. doi: 10.1161/01.atv.19.2.212.


Our study concerns the biological effects of abciximab (c7E3 Fab, ReoPro), a powerful new antiplatelet drug that blocks glycoprotein (GP) IIb-IIIa complexes. Samples were examined from 6 patients with coronary artery disease who received a bolus of abciximab followed by a 10- microg/min infusion for at least 18 hours before percutaneous transluminal coronary angioplasty. Inhibition of ADP-induced PA was maximal for 4 patients but partial (79% and 53%) for 2 others during the infusion. Flow cytometry performed with monoclonal antibodies (PAC-1, AP-6, and F26) specific for the "activated" GP IIb-IIIa complex revealed large decreases in the expression of activation markers on platelets during therapy, but these decreases were less marked when inhibition of ADP-induced PA was incomplete. Residual aggregation was seen for all patients during the infusion when TRAP 14-mer peptide or thrombin was the stimulus. Unblocked GP IIb-IIIa complexes were detected on thrombin-stimulated platelets from the patients by immunoelectron microscopy performed using the monoclonal antibody AP-2. Unblocked GP IIb-IIIa complexes were also detected by flow cytometry when platelets preincubated for 1 hour in vitro with abciximab under saturating conditions were (1) incubated with TRAP 14-mer or (2) permeabilized with Triton X-100. In confirming interpatient variation in the platelet response to a standard dose of abciximab, our results also show that an uninhibited internal pool of GP IIb-IIIa complexes may mediate a residual response to strong agonists.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abciximab
  • Aged
  • Angina, Unstable / therapy
  • Angioplasty, Balloon, Coronary
  • Antibodies, Monoclonal / therapeutic use*
  • Biomarkers
  • Blood Platelets / metabolism
  • Humans
  • Immunoglobulin Fab Fragments / therapeutic use*
  • Male
  • Middle Aged
  • Platelet Activation / drug effects*
  • Platelet Activation / physiology*
  • Platelet Aggregation / drug effects
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Platelet Glycoprotein GPIIb-IIIa Complex / metabolism
  • Preoperative Care


  • Antibodies, Monoclonal
  • Biomarkers
  • Immunoglobulin Fab Fragments
  • Platelet Aggregation Inhibitors
  • Platelet Glycoprotein GPIIb-IIIa Complex
  • Abciximab