The Role of Neutrophilic Granulocytes in Philadelphia Chromosome Negative Myeloproliferative Neoplasms

Philadelphia chromosome negative myeloproliferative neoplasms (MPN) are composed of polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). The clinical picture is determined by constitutional symptoms and complications, including arterial and venous thromboembolic or hemorrhagic events. MPNs are characterized by mutations in JAK2, MPL, or CALR, with additional mutations leading to an expansion of myeloid cell lineages and, in PMF, to marrow fibrosis and cytopenias. Chronic inflammation impacting the initiation and expansion of disease in a major way has been described. Neutrophilic granulocytes play a major role in the pathogenesis of thromboembolic events via the secretion of inflammatory markers, as well as via interaction with thrombocytes and the endothelium. In this review, we discuss the molecular biology underlying myeloproliferative neoplasms and point out the central role of leukocytosis and, specifically, neutrophilic granulocytes in this group of disorders.

Automated summary

Philadelphia chromosome negative myeloproliferative neoplasms consist of polycythemia vera, essential thrombocytosis, and primary myelofibrosis. Mutations in JAK2, MPL, or CALR characterize these disorders, with additional mutations leading to myeloid cell lineages expansion and marrow fibrosis in PMF. Chronic inflammation plays a significant role in the disease initiation and progression, with neutrophilic granulocytes playing a major role in the pathogenesis of thromboembolic events.