IL31 and acquired polycythemia vera: Finally, our finding of very high serum levels of IL-33 and IL-31 in a CML patient undergoing imatinib mesylate treatment compared to healthy controls has a more relevant significance in light of previous works, where we found a significant decrease of IL-33 plasma levels in patients affected by myeloproliferative disorders such as polycythemia vera and essential thrombocythemia and in subjects with other hematologic diseases [28,29,30].