To quantify CEC and CEP in patients with venous thromboembolism (VTE) and with myeloproliferative neoplasms (MPN), to characterize the CEC for the expression of activation (CD54, CD62E) and procoagulant (CD142) markers and to investigate whether they correlate with other clinical and laboratory data. Here, ICAM1 is linked to myeloproliferative disorder.