Inhibition of interleukin-1ß reduces myelofibrosis and osteosclerosis in mice with JAK2-V617F driven myeloproliferative neoplasm.

Interleukin-1ß (IL-1ß) is a master regulator of inflammation. Increased activity of IL-1ß has been implicated in various pathological conditions including myeloproliferative neoplasms (MPNs). Here we show that IL-1ß serum levels and expression of IL-1 receptors on hematopoietic progenitors and stem cells correlate with JAK2-V617F mutant allele fraction in peripheral blood of patients with MPN. We show that the source of IL-1ß overproduction in a mouse model of MPN are JAK2-V617F expressing hematopoietic cells. Knockout of IL-1ß in hematopoietic cells of JAK2-V617F mice reduces inflammatory cytokines, prevents damage to nestin-positive niche cells and reduces megakaryopoiesis, resulting in decrease of myelofibrosis and osteosclerosis. Inhibition of IL-1ß in JAK2-V617F mutant mice by anti-IL-1ß antibody also reduces myelofibrosis and osteosclerosis and shows additive effects with ruxolitinib. These results suggest that inhibition of IL-1ß with anti-IL-1ß antibody alone or in combination with ruxolitinib could have beneficial effects on the clinical course in patients with myelofibrosis.