Treatment of hypereosinophilic syndromes--the first 100 years.

Treatment of the hypereosinophilic syndrome (HES) has advanced rapidly and prevention of end organ damage previously associated with the disorders is now possible in most patients who have had a timely diagnosis. Tried and true medications such as prednisone, hydroxyurea, and interferon-alpha (IFN-aα) continue to play a valuable role in treating HES and their cost is modest. Newer medications included pegylated forms of IFN-aα and IFN-α2b, first- and second-generation tyrosine kinase inhibitors (imatinib mesylate, nilotinib), and monoclonal antibodies to interleukin (IL)-5 and CD52. The combination of better understanding of HES and better medications now provide the clinician with an improved ability to control unregulated proliferation of eosinophils.