IDIOPATHIC HYPEREOSINOPHILIC SYNDROME IN A PEDIATRIC PATIENT TREATED WITH BENRALIZUMAB

摘要

IntroductionHypereosinophilic syndrome (HES) is a diverse group of disorders with eosinophilia and end-organ damage. There are several subtypes of HES and Idiopathic HES (I-HES) is diagnosed by exclusion. There is limited literature about I-HES treatment in pediatrics and this is the first known report of benralizumab (anti-IL5Ra monoclonal antibody) in a child with I-HES. Case DescriptionA 9-year-old female presented with two months of vomiting, diarrhea, and weight loss in the setting of two years of chronic rash (presumed eczema, treated with immunosuppressants) and peripheral eosinophilia (peak absolute eosinophil count (AEC) of 5500). She developed pleural effusions (with 33% eosinophils) and acute heart failure, treated with high-dose corticosteroids with rapid clinical improvement. Bone marrow biopsy, T-cell receptor studies, cytogenetics, FISH, and whole exome sequencing were unremarkable. She was discharged on prednisone but could not taper below 15 mg/day. She failed a trial of imatinib due to diarrhea and erythroderma. Nine months post-discharge, she developed septic shock, complicated by acute kidney injury, dysrhythmias and cardiac arrest. The AEC peaked at 4470 and she received high-dose intravenous steroids and benralizumab with resolution of renal and cardiac dysfunction. AEC remains undetectable after three doses of benralizumab and only physiologic hydrocortisone dosing. DiscussionHES is more commonly seen in adults, but has been reported in pediatrics. First-line therapy is corticosteroids, but there are promising reports with mepolizumab (anti-IL5 antibody). This is the first known report of the successful use of an anti-IL5Ra monoclonal antibody in a pediatric patient with I-HES.