Platelet Activation in Myeloproliferative Disorders

Summary

Beta-thromboglobulin (beta-TG) and platelet factor four (PF4) are specific platelet proteins released when a process of platelet activation occurs.

The present study was undertaken in order to measure beta-TG and PF4 both as absolute plasma value and ratio to platelet number in 69 patients with myeloproliferative disorders (MD). The aim was to establish whether the increase of the two proteins could depend on platelet number or indicated an “in vivo” platelet activation.

In 74% of patients beta-TG was found elevated and PF4 was high in 68% of cases. However in 34.7% and in 31.9% of cases respectively, the elevation of the two platelet markers was correlated to platelet number and the ratio was normal. Only in about one third of cases an “in vivo” platelet activation could be admitted and this finding provides a more rational use of antiaggregating agents.

Keywords

Myeloproliferative disorders - Platelets - Beta-thromboglobulin - Platelet factor four

• References

• 1 Walsh PN, Murphy S, Barry WE. The role of platelets in the pathogenesis of thrombosis and hemorrhage in patients with thrombocytosis. Thromb Haemostas 1977; 38: 1085-1096
• 2 Wu KK. Platelet hyperaggregability and thrombosis in patients with thrombocythemia. Ann Int Med 1978; 88: 07-11
• 3 Cooper B, Schafer AI, Puchalsky D, Handin RI. Platelet resistance to prostaglandin D₂ in patients with myeloproliferative disorders. Blood 1978; 53: 618-626
• 4 Dawes J, Smith RC, Pepper DS. The release, distribution and clearance of human β-thromboglobulin and platelet factor four. Thromb Res 1978; 12: 851-861
• 5 Zahavi J, Kakkar VV. β-thromboglobulin-a specific marker of in vivo platelet release reaction. Thromb Haemostas 1980; 44: 23-29
• 6 Boughton BJ, Allington MJ, King A. Platelet and plasma β-thromboglobulin in myeloproliferative syndromes and secondary thrombocytosis. Br J Haemat 1978; 40: 125-132
• 7 Schemthaner G, Ludwig H, Silberbauer K. Elevated plasma β-thromboglobulin levels in multiple myeloma and polycythaemia vera. Acta haemat 1979; 62: 219-222
• 8 Berlin NI. Diagnosis and classification of the polycythemias. Semin Hematol 1975; 12: 339-351
• 9 Gunz FW. Hemorrhagic thrombocythemia. A critical review. Blood I 1960; 15: 706-723
• 10 Lazlo J. Myeloproliferative disorders (MPD). Myelofibrosis, myelosclerosis, extramedullary hematopoiesis, undifferentiated MPD, and hemorrhagic thrombocythemia. Semin Hematol 1975; 12: 409-432
• 11 Rundles RW. Chronic granulocytic leukemia. In: Williams WJ, Beutler E, Erslev AJ, Rundles RW. eds Hematology. New York: Mc Graw Hill; 1977: 777-796
• 12 Zahavi J, Cella G, Dubiel M, Kakkar VV. The variability of plasma β-thromboglobulin in healthy individuals. Thromb Haemostas 1978; 40: 565-567
• 13 Zahavi J, Jones NAG, Leyton J, Dubiel M, Kakkar VV. Enhanced in vivo platelet “release reaction” in old healthy individuals. Thromb Res 1980; 17: 329-336