Platelet GP IIIa Pl(A) polymorphisms display different sensitivities to agonists

Alan D. Michelson, Mark I. Furman, Pascal Goldschmidt-Clermont, Mary Ann Mascelli, Craig Hendrix, Lindsay Coleman, Jeanette Hamlington, Marc R. Barnard, Thomas Kickler, Douglas J. Christie, Sourav Kundu, Paul F. Bray

Research output: Contribution to journalArticlepeer-review

322 Scopus citations


Background - Both inherited predisposition and platelet hyperreactivity have been associated with ischemic coronary events, but mechanisms that support genetic differences among platelets from different subjects are generally lacking. Associations between the platelet Pl(A2) polymorphism of GP IIIa and coronary syndromes raise the question as to whether this inherited variation may contribute to platelet hyperreactivity. Methods and Results - In this study, we characterized functional parameters in platelets from healthy donors with the Pl(A) (HPA-1) polymorphism, a Leu (Pl(A1)) to Pro (Pl(A2)) substitution at position 33 of the GP IIIa subunit of the platelet GP IIb/IIIa receptor (integrin α(IIb)β33). We studied 56 normal donors (20 Pl(A1,A1), 20 Pl(At,A2), and 16 Pl(A2,A2)). Compared with Pl(At,A1) platelets, Pl(A2)-positive platelets showed a gene dosage effect for significantly greater surface-expressed P-selectin, GP IIb/IIIa-bound fibrinogen, and activated GP IIb/IIIa in response to low-dose ADP. Surface expression of GP IIb/IIIa was similar in resting platelets of all 3 genotypes but was significantly greater on Pl(A2,A2) platelets after ADP stimulation (P=0.003 versus Pl(A1,A1); P=0.03 versus Pl(A1,A2)). Pl(A1,A2) platelets were more sensitive to inhibition of aggregation by pharmacologically relevant concentrations of aspirin and abciximab. Conclusions - Pl(A2)-positive platelets displayed a lower threshold for activation, and platelets heterozygous for Pl(A) alleles showed increased sensitivity to 2 antiplatelet drugs. These in vitro platelet studies may have relevance for in vivo thrombotic conditions.

Original languageEnglish (US)
Pages (from-to)1013-1018
Number of pages6
Issue number9
StatePublished - Mar 7 2000


  • Coronary disease
  • Inhibitors
  • Platelets
  • Polymorphisms

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


Dive into the research topics of 'Platelet GP IIIa Pl(A) polymorphisms display different sensitivities to agonists'. Together they form a unique fingerprint.

Cite this