Chronic neutrophilic leukemia (CNL) is a rare type of leukemia characterized by a proliferation mainly of mature neutrophils, elevated neutrophil-alkaline phosphatase activity, and no presence of the Philadelphia chromosome. The prognosis is generally poor and there is no consensus therapeutic strategy for the treatment of this disease. The JAK2 V617F mutation has been detected in patients with classical myeloproliferative disorders (MPD) including polycythemia vera and essential thrombocythemia and idiopathic myelofibrosis. In contrast, this same mutation has been detected in only 4 patients with CNL to date, suggesting that the JAK2 V617F mutation is a rare event in patients with atypical MPD. Here, we report a case of CNL with presence of the JAK2 V617F mutation. After treatment with interferon alfa-2b with 3 million units every other day for 1 month, the patient’s white blood cell count was well controlled below 10.0 ×109/l. At present, our patient remains symptomatically well and is maintained on interferon alfa-2b (3 million units twice a week), and his neutrophil count now averages around 8.0–10.0 ×109/l.

1.
Elliott MA, Dewald GW, Tefferi A, Hanson CA: Chronic neutrophilic leukemia (CNL): a clinical, pathologic and cytogenetic study. Leukemia 2001;15:35–40.
2.
Elliott MA, Hanson CA, Dewald GW, Smoley SA, Lasho TL, Tefferi A: WHO-defined chronic neutrophilia leukemia: a long-term analysis of 12 cases and a critical review of the literature. Leukemia 2005;19:313–317.
3.
Steensma DP, Dewald GW, Lasho TL, Powell HL, McClure RF, Levine RL, Gary Gilliland D, Tefferi A: The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both ‘atypical’ myeloproliferative disorders and myelodysplastic syndromes. Blood 2005;106:1207–1209.
4.
Mc Lornan DP, Percy MJ, Jones AV, Cross NC, Mc Mullin MF: Chronic neutrophilic leukemia with an associated V617F JAK2 tyrosine kinase mutation. Haematologica 2005;90:1696–1697.
5.
Lea NC, Lim Z, Westwood NB, Arno MJ, Gaken J, Mohamedali A, Mufti GJ: Presence of JAK2 V617F tyrosine kinase mutation as a myeloid-lineage-specific mutation in chronic neutrophilic leukemia. Leukemia 2006;20:1324–1326.
6.
Kako S, Kanda Y, Sato T, Goyama S, Noda N, Shoda E, Oshima K, Inoue M, Izutsu K, Watanabe T, Motokura T, Chiba S, Fukayama M, Kurokawa M: Early relapse of JAK2 V617F-positive chronic neutrophilic leukemia with central nervous system infiltration after unrelated bone marrow transplantation. Am J Hematol 2007;82:386–390.
7.
Kralovics R, Passamonti F, Buser AS, Teo SS, Tiedt R, Passweg JR, Tichelli A, Cazzola M, Skoda RC: A gain-of-function mutation of JAK2 in myeloproliferative disorders. N Engl J Med 2005;352:1779–1790.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.