Polycythaemia vera

Polycythaemia vera (PV) is generally a disease of middle and older age.

Carries increased risks of thrombosis, haemorrhage, progression to myelofibrosis, and transformation to acute leukaemia.

Life expectancy is reported to be modestly reduced compared with that of the general population. Leading causes of death are cardiovascular complications (including thrombosis and haemorrhage) and transformation to acute myeloid leukaemia.

Diagnosis is strongly associated with the presence of the JAK2 V617F mutation, although this mutation is not specific for PV.

Treatment is based on stratification for risk of thrombosis, and includes low-dose aspirin and phlebotomy for all patients. High-risk patients also receive cytoreductive therapy.

PV is a chronic myeloproliferative neoplasm. It is characterised by haematopoietic stem cell-derived clonal myeloproliferation that results in erythrocytosis and often thrombocytosis, leukocytosis, and splenomegaly.[1]Adamson JW, Fialkow PJ, Murphy S, et al. Polycythemia vera: stem-cell and probable clonal origin of the disease. N Engl J Med. 1976 Oct 21;295(17):913-6. http://www.ncbi.nlm.nih.gov/pubmed/967201?tool=bestpractice.com PV is associated with an increased risk of thrombosis and haemorrhage.[2]Elliott MA, Tefferi A. Thrombosis and haemorrhage in polycythaemia vera and essential thrombocythaemia. Br J Haematol. 2005 Feb;128(3):275-90. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2141.2004.05277.x http://www.ncbi.nlm.nih.gov/pubmed/15667529?tool=bestpractice.com ​​

PV may progress to spent phase (post-PV myelofibrosis) and, uncommonly, to a devastating acute leukaemia. Diagnosis is strongly associated with the presence of the Janus kinase 2 (JAK2) V617F somatic driver mutation, although this mutation is not specific for PV.[3]James C, Ugo V, Le Couedic JP, et al. A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. Nature. 2005 Apr 28;434(7037):1144-8. http://www.ncbi.nlm.nih.gov/pubmed/15793561?tool=bestpractice.com [4]Kralovics R, Passamonti F, Buser AS, et al. A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med. 2005 Apr 28;352(17):1779-90. http://www.nejm.org/doi/full/10.1056/NEJMoa051113#t=article http://www.ncbi.nlm.nih.gov/pubmed/15858187?tool=bestpractice.com [5]Baxter EJ, Scott LM, Campbell PJ, et al. Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders. Lancet. 2005 Mar 19-25;365(9464):1054-61. http://www.ncbi.nlm.nih.gov/pubmed/15781101?tool=bestpractice.com ​​[6]Levine RL, Wadleigh M, Cools J, et al. Activating mutation in the tyrosine kinase JAK2 in polycythaemia vera, essential thrombocythemia and myeloid metaplasia with myelofibrosis. Cancer Cell. 2005 Apr;7(4):387-97. http://www.ncbi.nlm.nih.gov/pubmed/15837627?tool=bestpractice.com