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Elevated leukocyte counts are common and are associated with increased risks

Elevated leukocyte counts increase the risk of thrombosis1

  • Risk is clearly increased in patients with leukocyte counts >7 x 109/L
  • Risk becomes statistically significant when the count is ≥11 x 109/L (HR=3.90; 95% CI, 1.24-12.3; P=0.02)

Elevated leukocyte counts2

Elevated leukocyte counts in Polycythemia Vera (PV) – JAKAVI
  • In a retrospective chart review of 1080 patients currently receiving HU, 58.2% had elevated leukocyte counts (>10 x 109/L)2

Elevated leukocyte counts may increase risk of thrombosis by 70%3

  • Supplemental phlebotomy does not reduce leukocyte or platelet counts in PV4

Learn about leukocyte control with JAKAVI

Next: Patients with PV experience burdensome symptoms



  1. Barbui T, Masciulli A, Marfisi MR, et al. White blood cell counts and thrombosis in polycythemia vera: a subanalysis of the CYTO-PV study [Correspondence]. Blood. 2015;126(4):560-561.
  2. Parasuraman S, DiBonaventura M, Reith K, Concialdi K. Treatment patterns and hydroxyurea response among patients with polycythemia vera. Presented at: 56th ASH Annual Meeting and Exposition; December 6-9, 2014; San Francisco, CA.
  3. Landolfi R, Di Gennaro L, Barbui T, et al; for the European Collaboration on Low-Dose Aspirin in Polycythemia Vera (ECLAP). Leukocytosis as a major thrombotic risk factor in patients with polycythemia vera. Blood. 2007;109(6):2446-2452.
  4. Prchal JT, Prchal JF. Polycythemia vera. In: Kaushansky K, Lichtman MA, Beutler E, Kipps TJ, Seligsohn U, Prchal JT. Williams Hematology. 8th ed. New York: McGraw-Hill; 2010:chapter 86. Accessed April 10, 2015.