Clinical Manifestations and Risk Factors for Complications of Philadelphia Chromosome-Negative Myeloproliferative Neoplasms


Background: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterizedby proliferation of one or more myeloid lineages. Polycythemia vera (PV), essential thrombocythemia (ET)and primary myelofibrosis (PMF) are classical Philadelphia chromosome (Ph)-negative MPN that have aJanus Kinase 2 (JAK2) mutation, especially JAK2V617F in the majority of patients. The major complicationsof Ph-negative MPNs are thrombosis, hemorrhage, and leukemic transformation.
Objective: To study clinicalmanifestations including symptoms, signs, laboratory findings, and JAK2V617F mutations of Ph-negative MPN(PV, ET and PMF) as well as their complications. Materials and
Methods: All Ph-negative MPN (PV, ET andPMF) patients who attended the Hematology Clinic at Maharaj Nakorn Chiang Mai Hospital from January, 12003 through December, 31 2013 were retrospectively reviewed for demographic data, clinical characteristics,complete blood count, JAK2V617F mutation analysis, treatment, and complications.
Results: One hundred andfifty seven patients were included in the study. They were classified as PV, ET and PMF for 68, 83 and 6 withmedian ages of 60, 61, and 68 years, respectively. JAK2V617F mutations were detected in 88%, 69%, and 100%of PV, ET and PMF patients. PV had the highest incidence of thrombosis (PV 29%, ET 14%, and PMF 0%)that occurred in both arterial and venous sites whereas PMF had the highest incidence of bleeding (PMF 17%,ET 11%, and PV 7%). During follow up, there was one ET patient that transformed to acute leukemia and fivecases that developed thrombosis (three ET and two PV patients). No secondary myelofibrosis and death caseswere encountered.
Conclusions: Ph-negative MPNs have various clinical manifestations. JAK2V617F mutationsare present in the majority of PV, ET, and PMF patients. This study confirmed that thrombosis and bleedingare the most significant complications in patients with Ph-negative MPN.