IL4 and myeloproliferative neoplasm: Aberrant proinflammatory signaling stands out as a defining feature of MPN, particularly evident in Overt-PMF, a series of interleukins (IL) and cytokines had been reported to be associated with pathogenesis of MPN, including IL-1β, IL-2R, IL-6, IL-8, IL-10, TNF-α, TGF-β and more, while CXCL4, CXCL8 and IL-4 were reported to associated with fibrotic progression (10–14).