Inflammation and Thrombosis In Essential Thrombocythemia

Abstract 5175

The essential thrombocythemia (ET) is a myeloid neoplasm characterized by an inflammatory component responsible for coagulant activation and angiogenesis. Therefore, we evaluated platelets, interleukin-8 (IL-8) and interleukin-15 (IL-15), as inflammatory indicators, tissue factor (TF), as marker of coagulative activation, and vascular endothelial growth factor (VEGF), as indicator of angiogenesis, in patients with ET and thrombosis. We recruited 25 thrombocythemic patients (10 males and 15 females, mean age 58 years) who fulfilled WHO.criteria. Their mean duration of disease was 8 years (range, 5–21 years). All patients were on aspirin. None of the patients had thrombotic risk factors. Of 25 patients, 10 developed thrombosis including 5 episodes of microvascular thrombosis of extremities (erythromelalgia), 2 of transient ischemic attack (TIA), 2 of myocardial infarction (IMA) and 1 of deep vein thrombosis (DVT)) whereas 15 did not. Platelets were measured by automated analyser. IL-8, IL-15, and VEGF and DD were measured by ELISA and immunoturbidimetric assay, respectively. All patients had thrombocytosis (961±235×109/L). IL-8, IL-15, TF and VEGF^PLT were higher in patients with thrombosis than patients without thrombosis (27±14 pg/ml and 14±4 pg/ml and 214±266 pg/ml and 2±1 pg/10⁶l vs 14±7 pg/ml and 26±6 pg/ml and 108±64 μg/l and 1±0.9 pg/ml, respectively) (p=0.009 and p<.0001 and p=0.005 and p=0.059, respectively). A positive correlation there was between IL-8 and IL-15 (p<.0001) and between IL-15 and TF (p=0.046). A tendency towards correlation was found between IL-15 and VEGF (p=0.082). These findings suggest a inflammatory IL-8-IL-15 interplay responsible for coagulation and angiogenesis activation that might mean increased thrombophilia in ET.