title: Human platelets secrete chemotactic activity for eosinophils.
abstract: Thrombin-stimulated platelets liberate factors that induce chemotaxis of eosinophils and raise their cytosolic Ca2+ content ([Ca2+]i). The sources of this activity are the dense- and alpha-granules because inhibition of prostaglandin endoperoxide/thromboxane A2 formation and the platelet-activating factor receptor-antagonist WEB 2086 have no effect. Platelets from patients with Storage-Pool Deficiency show about 60% of the normal chemotactic activity with little effect on [Ca2+]i, whereas completely degranulated platelets fail to affect eosinophils. In concentrations secreted by the platelets, adenosine diphosphate (ADP), and platelet factor 4 have no effect, whereas adenosine triphosphate (ATP) induces a strong chemotactic response and increases [Ca2+]i. However, apart from ATP other modulating factors must be involved as platelet releasates induce more chemotaxis than ATP alone. Thus, platelets secrete factors that activate eosinophils and may contribute to inflammatory and allergic processes.
authors.affiliation: Department of Hematology, University Hospital Utrecht, The Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: Burgers
authors.forename: R C
authors.initials: RC
authors.lastname: Schweizer
authors.forename: L
authors.initials: L
authors.lastname: Koenderman
authors.forename: P L
authors.initials: PL
authors.lastname: Bruijnzeel
authors.forename: J W
authors.initials: JW
authors.lastname: Akkerman
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001381:Azepines / Q000494:pharmacology; D001792:Blood Platelets / Q000502:physiology* / Q000648:ultrastructure; D002118:Calcium / Q000378:metabolism; D002630:Chemotactic Factors / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte; D003594:Cytoplasmic Granules / Q000502:physiology; D003600:Cytosol / Q000378:metabolism; D004804:Eosinophils / Q000502:physiology*; D006801:Humans; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors; D010978:Platelet Factor 4 / Q000494:pharmacology; D010981:Platelet Storage Pool Deficiency / Q000503:physiopathology; D011449:Prostaglandin Endoperoxides / Q000037:antagonists & inhibitors; D013928:Thromboxane A2 / Q000037:antagonists & inhibitors; D014230:Triazoles / Q000494:pharmacology
chemical_list: D001381:Azepines; D002630:Chemotactic Factors; D010972:Platelet Activating Factor; D011449:Prostaglandin Endoperoxides; D014230:Triazoles; C052518:WEB 2086; D010978:Platelet Factor 4; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002118:Calcium