title: Simultaneous measurement of adenosine triphosphate release and aggregation potentiates human platelet aggregation responses for some subjects, including persons with Quebec platelet disorder.
abstract: Platelet aggregometry and dense granule adenosine triphosphate (ATP) release assays are helpful to diagnose platelet disorders. Some laboratories simultaneously measure aggregation and ATP release using Chronolume® a commercial reagent containing D-luciferin, firefly luciferase and magnesium. Chronolume® can potentiate sub-maximal aggregation responses, normalising canine platelet disorder findings. We investigated if Chronolume® potentiates human platelet aggregation responses after observing discrepancies suspicious of potentiation. Among patients simultaneously tested by light transmission aggregometry (LTA) on two instruments, 18/43 (42%), including 14/24 (58%) with platelet disorders, showed full secondary aggregation with one or more agonists only in tests with Chronolume®. As subjects with Quebec platelet disorder (QPD) did not show the expected absent secondary aggregation responses to epinephrine in tests with Chronolume®, the reason for the discrepancy was investigated using samples from 10 QPD subjects. Like sub-threshold ADP (0.75 μM), Chronolume® significantly increased QPD LTA responses to epinephrine (p<0.0001) and it increased both initial and secondary aggregation responses, leading to dense granule release. This potentiation was not restricted to QPD and it was mimicked adding 1-2 mM magnesium, but not D-luciferin or firefly luciferase, to LTA assays. Chronolume® potentiated the ADP aggregation responses of QPD subjects with a reduced response. Furthermore, it increased whole blood aggregation responses of healthy control samples to multiple agonists, tested at concentrations used for the diagnosis of platelet disorders (p values <0.05). Laboratories should be aware that measuring ATP release with Chronolume® can potentiate LTA and whole blood aggregation responses, which alters findings for some human platelet disorders, including QPD.
authors.affiliation: 1Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. Canadahaywrdc@mcmaster.ca
authors.forename: C P M
authors.initials: CP
authors.lastname: Hayward
authors.forename: K A
authors.initials: KA
authors.lastname: Moffat
authors.forename: J-F
authors.initials: JF
authors.lastname: Castilloux
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Seecharan
authors.forename: S
authors.initials: S
authors.lastname: Tasneem
authors.forename: S
authors.initials: S
authors.lastname: Carlino
authors.forename: A
authors.initials: A
authors.lastname: Cormier
authors.forename: G E
authors.initials: GE
authors.lastname: Rivard
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000378:metabolism*; D052160:Benzothiazoles / Q000378:metabolism; D001792:Blood Platelets / Q000378:metabolism; D016022:Case-Control Studies; D004837:Epinephrine / Q000737:chemistry; D005166:Factor V Deficiency / Q000097:blood* / Q000378:metabolism; D006801:Humans; D007202:Indicators and Reagents / Q000494:pharmacology; D008027:Light; D008156:Luciferases / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010979:Platelet Function Tests / Q000379:methods; D013997:Time Factors
chemical_list: D052160:Benzothiazoles; C532924:D-luciferin; D007202:Indicators and Reagents; D010975:Platelet Aggregation Inhibitors; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008156:Luciferases; D008274:Magnesium; D004837:Epinephrine