Role of Myeloid-derived Suppressor Cells In Primary Myelofibrosis

The goals of this observational study are to investigate the role of myeloid-derived suppressor cells (MDSCs) in fueling chronic inflammation that is a relevant pathogenetic mechanism in patients with primary myelofibrosis (PMF), to study modifications in MDSC phenotype and function after treatment with JAK-inhibitors (JAK-i) and to test their participation in the neoangiogenic process. The main questions it aims to answer are: * Do the frequency and function of MDSCs contribute to induce or sustain the inflammatory status that characterizes PMF? * Does the number of circulating MDSCs in PMF patients correlate with clinical/biological parameters? * Are MDSCs involved in the neoangiogenic processes that characterizes PMF?