title: Quantitation of platelet aggregation and microaggregate formation in whole blood by flow cytometry.
abstract: Platelet aggregation and microaggregate formation were measured in samples of stirred whole blood by flow cytometry. Blood samples were stirred in a multi-sample agitator with ADP, fixed and labelled with a platelet-specific CD42a-FITC fluorescent antibody. The blood was then diluted and applied directly to a flow cytometer. Platelets were identified using a gating procedure based on their expression of CD42a and then quantified. Aggregation was monitored as a fall in the number of single platelets. Both reversible and irreversible aggregation responses to ADP were determined and these were found to correlate directly with aggregation responses determined using a well-established single platelet counting technique using the Ultra-Flo 100 Whole Blood Platelet Counter. We found from flow cytometry that ADP-induced aggregation was coupled with a transient formation of platelet microaggregates over the initial 60 s following ADP addition. Assessment of single platelet loss by flow cytometry was found to be a reliable way of monitoring aggregation responses and provided new information on rapid microaggregate formation in ADP-stimulated blood.
authors.affiliation: Cardiovascular Medicine, University Hospital, Queen's Medical Centre, Nottingham NG7 2UH, UK. sue.fox@nottingham.ac.uk
authors.forename: S C
authors.initials: SC
authors.lastname: Fox
authors.forename: R
authors.initials: R
authors.lastname: Sasae
authors.forename: S
authors.initials: S
authors.lastname: Janson
authors.forename: J A
authors.initials: JA
authors.lastname: May
authors.forename: S
authors.initials: S
authors.lastname: Heptinstall
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D001773:Blood Cells; D001792:Blood Platelets / Q000166:cytology; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D017730:Ki-1 Antigen; D010974:Platelet Aggregation; D010976:Platelet Count / Q000295:instrumentation / Q000379:methods
chemical_list: D017730:Ki-1 Antigen; D000244:Adenosine Diphosphate