title: Increased platelet surface expression of P-selectin and thrombospondin as markers of platelet activation in essential thrombocythaemia.
abstract: Essential thrombocythaemia (ET) is a clonal myeloproliferative disorder associated with an increased risk of both thromboembolic and bleeding complications. Platelet activation plays a crucial role in the pathogenesis of prethrombotic conditions. The platelet surface expression of p-selectin (CD62p) and thrombospondin (TSP) has been shown to correlate with platelet activation. In the present study, we used a flow cytometric assay to study whether the fraction of platelets expressing CD62p and TSP is increased in newly diagnosed ET. Thirty-four patients with newly diagnosed ET and 25 healthy control subjects were investigated. The proportion of platelets expressing the activation-dependent antigens CD62p and TSP was higher in patients with ET (CD62p: 14.7+/-15.0%; TSP: 12.4+/-9.9%) as compared with healthy control subjects (CD62p: 3.0+/-4.0%; TSP: 3.2+/-3.2%; p< 0.001). In ET, there was a linear correlation between platelet surface expression of CD62p and TSP (p<0.0001, r=0.83). At diagnosis of ET, 20 patients were symptomatic and 14 asymptomatic. Compared with asymptomatic ET patients there was no difference in the expression of CD62p (18.3+/-16.2% vs. 14.5+/-13.4%) and TSP (14.4+/-9.8% vs. 12.8+/-9.5%) in symptomatic ET patients. In conclusion, increased expression of platelet neoantigens is present at the diagnosis of ET. Both activation-dependent epitopes CD62p and TSP are increasingly expressed on the platelet surface in newly diagnosed ET patients.
authors.affiliation: Department of Haematology and Oncology, Infectious Diseases and Haemostaseology, University of Ulm, Federal Republic of Germany. martin.griesshammer@medizin.uni-ulm.de
authors.forename: M
authors.initials: M
authors.lastname: Griesshammer
authors.forename: H
authors.initials: H
authors.lastname: Beneke
authors.forename: B
authors.initials: B
authors.lastname: Nussbaumer
authors.forename: M
authors.initials: M
authors.lastname: Grünewald
authors.forename: M
authors.initials: M
authors.lastname: Bangerter
authors.forename: L
authors.initials: L
authors.lastname: Bergmann
mesh_terms: D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D008875:Middle Aged; D019007:P-Selectin / Q000096:biosynthesis* / Q000235:genetics; D015539:Platelet Activation / Q000187:drug effects; D011446:Prospective Studies; D013920:Thrombocythemia, Essential / Q000097:blood* / Q000188:drug therapy; D019699:Thrombospondins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D019007:P-Selectin; D019699:Thrombospondins; D001241:Aspirin