Chronic myeloproliferative disorders (CMPD) are classified according to the WHO classification of 2001 as polycythemia vera (PV), chronic idiopathic myelofibrosis (CIMF), essential thrombocythemia (ET), CMPD/unclassifiable (CMPD-U), chronic neutrophilic leukemia, and chronic eosinophilic leukemia (CEL)/hypereosinophilic syndrome, all to be delineated from BCR/ABL-positive chronic myeloid leukemia (CML).
Hypereosinophilic syndromes (HES) and systemic mastocytosis (SMCD) are heterogeneous disorders with clinical symptoms from local and remote effects of excessive proliferation of eosinophils and mast cells, respectively. Interferon alpha (IFN-alpha), alone or in combination with other medications, can be a useful, and at times life-saving, treatment for patients with HES. Receptors for IFN-alpha are present on eosinophils, and clinical benefits are due to its effect on eosinophil proliferation, migration, activation, and survival. These effects are likely mediated through multiple pathways including, but not limited to, inhibition of eosinophil colony-forming cells, upregulation of IFN-gamma synthesis, and inhibition of production of eosinophil-active cytokines by T cells, mast cells, and mononuclear cells. A number of case reports showed that IFN-alpha has been life-saving for patients with intractable HES that were resistant to prednisone, hydroxyurea, and other agents. There are reports of combined use with hydroxyurea and prednisone. There are also reports of the use of peg-interferon.
Unfortunately, HES is rare and prospective trials are not reasonable to expect. I did find that PDQ from the National Cancer Institute recommended interferon for this disese.
Schnittger S, Schoch C.Modern diagnostics in chronic myeloproliferative diseases (CMPDs).Haferlach T, Kern W, Ann Hematol. 2004;83 Suppl 1:S59-61.
Butterfield JH.Interferon treatment for hypereosinophilic syndromes and systemic mastocytosis.Acta Haematol. 2005;114(1):26-40.
J. Butterfield PEG-Interferon after Interferon alfa-2b for Hypereosinophilic Syndrome
Journal of Allergy and Clinical Immunology, Volume 119, Issue 1, Pages S222-S222
Butterfield JH, Weiler CR. Use of pegylated interferon in hypereosinophilic syndrome.Leuk Res. 2012 Feb;36(2):192-7.
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