Treatment of a case of pediatric hypereosinophilic syndrome with anti-interleukin-5.

We report the use of anti-interleukin-5 (mepolizumab) during an 18-month period in a pediatric hypereosinophilic syndrome. Infusions every 3 months allowed better control of hypereosinophilic syndrome flares and maintained blood eosinopenia with significantly less steroid use compared with all other therapies (prednisolone alone, interferon alpha, or imatinib mesylate).