Interleukin-15 Levels in Patients with Essential Thrombocythemia

Abstract 5071

The essential thrombocythemia (ET) is a myeloid neoplasm characterized by a inflammatory component responsible for myeloproliferation and hypercoagulability. It has been showed that interleukin-15 (IL-15) affects myelopoiesis and coagulation. Therefore, we evaluated platelets, hematocrit (HCT), as myeloproliferative indicator, tissue factor (TF), as marker of coagulative activation and IL-15. We recruited 25 patients with ET (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. Platelets and HCT were measured by automated analyser. IL-15 and TF were measured by ELISA. All patients had thrombocytosis (961±235×109/L), high HCT (42±4 vs 37±1 %) (p<. 0001), increased TF (214±266 pg/ml vs 5±3 pg/ml) (p<. 0001) and elevated IL-15 (21±8 pg/ml vs 2±1 pg/ml) (p<. 0001). A correlation there was between IL-15 and HCT (p=0. 076) and a strong correlation was found between IL-15 and TF (p=0. 046). These results suggest a novel relationship between IL-15 and myeloproliferation and thrombosis that might mean worse prognosis.