Blood Journal
Leading the way in experimental and clinical research in hematology

Polymorphonuclear leukocyte activation and hemostasis in patients with essential thrombocythemia and polycythemia vera

  1. Anna Falanga,
  2. Marina Marchetti,
  3. Virgilio Evangelista,
  4. Alfonso Vignoli,
  5. Marina Licini,
  6. Mara Balicco,
  7. Stefano Manarini,
  8. Guido Finazzi,
  9. Chiara Cerletti, and
  10. Tiziano Barbui
  1. 1 From the Hematology Division, Ospedali Riuniti, Bergamo; and the Mario Negri Institute for Pharmacological Research, Consorzio Mario Negri Sud, S. Maria Imbaro, Italy.

Abstract

Thrombohemorrhagic complications are a major cause of morbidity and mortality in patients with essential thrombocythemia (ET) and polycythemia vera (PV). The pathogenesis of these complications is not completely clarified. Several studies have described abnormalities of red blood cells and platelets in these patients. However, no studies are available on changes in the polymorphonuclear leukocytes (PMNs), which can play an important role in the activation of the hemostatic system. In patients with ET (n = 37) and PV (n = 34), a series of PMN activation parameters (PMN membrane CD11b and leukocyte alkaline phosphatase [LAP] antigen expression, cellular elastase content, plasma elastase, and myeloperoxidase levels) was evaluated simultaneously with the levels of plasma markers of endothelial damage (thrombomodulin and von Willebrand factor antigen) and hypercoagulation (thrombin-antithrombin complex, prothrombin fragment 1 + 2, and D-dimer). The results show the occurrence of PMN activation in both groups of patients compared with a control group of healthy subjects. An increase in CD11b and LAP expression by PMN membrane was observed, together with a significant increase in cellular elastase content, plasma elastase, and myeloperoxidase levels. In addition, patients had high plasma levels of endothelial and hypercoagulation markers compared with controls. For the first time, these data show that in ET and PV, 2 hematologic conditions that place patients at increased risk for thrombosis, an in vivo leukocyte activation occurs and is associated with laboratory signs of endothelium and coagulation system activation.

  • Submitted February 29, 2000.
  • Accepted August 30, 2000.
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