Circulating Polymorphonuclear Myeloid-Derived Suppressor Cells (PMN-MDSCs) Have a Biological Role in Patients with Primary Myelofibrosis.

Simple Summary: Myeloid-derived suppressor cells (MDSCs) are immature cells that expand in the circulation of patients with cancer, sepsis or chronic inflammation, modulate the immune response against cancer (favoring tumor onset and progression) and promote neoangiogenesis. These premises suggest that MDSCs could be involved in the pathogenesis of primary myelofibrosis (PMF) (a myeloproliferative neoplasm characterized by chronic inflammation and extensive neoangiogenesis in bone marrow and spleen). In this paper, we found that (1) MDSCs are increased both in the circulation and in the spleen of PMF patients and strongly correlate with disease progression; and (2) reduced CXCR4 expression on MDSCs along with increased plasmatic SDF-1α can be involved in their mobilization. These findings suggest that circulating MDSCs can be considered a parameter of disease severity and set MDSCs as potential new targets for cancer therapy. Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by a chronic inflammatory state that plays a relevant role in the disease pathogenesis (as proven by high levels of inflammatory cytokines with prognostic significance and by a persistent oxidative stress) and by extensive neoangiogenesis in bone marrow (BM) and spleen. Myeloid-derived suppressor cells (MDSCs) are immature cells that expand in patients with cancer, sepsis or chronic inflammation, favoring tumor onset and progression mainly through the decrease in immune surveillance and the promotion of neoangiogenesis. In this paper, we evaluated the presence of circulating MDSCs in PMF patients, the plasmatic factors involved in their mobilization/expansion and the correlations with laboratory, genetic and clinical parameters. The data indicated that MDSCs could have a relevant role in PMF as a new pathogenic mechanism contributing to explaining the phenotypic diversity observed during the clinical course of the disease, or a potential new target for personalized treatment. [ABSTRACT FROM AUTHOR]