Proliferative characteristics of Philadelphia-negative myeloproliferative neoplasms - clinical implications

Abstract

Introduction: Philadelphia-negative myeloproliferative neoplasms (Ph-MPN) are characterized by overproduction of one or more blood cell lines. Methods: We studied the proliferative characteristics of 91 patients with de novo Ph-MPN. Colony-forming cells (CFC) and endogenous colonies (EC), from bone marrow (BM) and/or peripheral blood (PB), were analyzed by colony assay based on methylcellulose. The level of circulating CD34(+) cells was determined by flow cytometry. Results: The total number of PB CFC in primary myelofibrosis (PMF) was increased compared to the control sample (P lt 0.01) and essential thrombocythemia (ET) (P lt 0.05). The highest number of BM and PB EC was observed in polycythemia vera (PV) (P lt 0.01). Increased levels of CD34(+) cells characterized early-prefibrotic (57%) and advanced-fibrotic PMF (90%) as compared to PV (34%) and ET (32%) (P lt 0.01). In the whole Ph-MPN group, the total number of PB CFC (P lt 0.01), PB EC (P lt 0.05), and CD34+ cells (P lt 0.01) correlated with the degree of BM fibrosis. Higher levels of circulating CD34(+) cells in PMF correlated with the total number of PB EC (P lt 0.05) and degree of BM fibrosis (P lt 0.01). Conclusions: Exploration of the PB proliferative characteristics of Ph-MPN on diagnosis may be helpful in revealing early-prefibrotic PMF. Monitoring the levels of circulating CD34(+) cells may provide a sensitive indicator of fibrotic evolution in PV and PMF.