Severe Idiopathic Hypereosinophilic Syndrome with Eosinophilic Cholecystitis in a Child Treated with Mepolizumab

Excerpt

To the Editor: A 14-y-old girl was admitted to rheumatology due to recurrent vasculitis-like rash, arthralgia of ankles, paresthesia in feet and intermittent abdominal pain. Laboratory work-up revealed a significant elevation in absolute eosinophil count (AEC) (1.94–8.04 X 10⁹/L; normal range: 0.05–0.5 X 10⁹/L), rheumatoid factor (RF) level (1370–4340 IU/mL; normal range: 0–15.9 IU/mL) and IL-5 (18.88 pg/mL; normal range: ≤3.1 pg/mL). Triple positivity of antiphospholipid syndrome (APS)-related antibodies was found [1]. Both bone marrow and intestinal biopsy showed eosinophilia infiltration. Neurogenic injury was defined by electromyography. Genetic testing (FIP1L1-PDGFRA) was negative. Thus, idiopathic hypereosinophilic syndrome (IHES) was diagnosed after excluding other causes of peripheral eosinophilia and glucocorticoids (GC) (2 mg/kg/d) were prescribed immediately. However, 3 wk later, acute cholecystitis, endocardial damage, pleural effusion and re-elevated AEC prompted administration of imatinib. However, only incomplete remission was observed complicated with hypertension after 3 mo, so mepolizumab, a targeted, humanized, monoclonal anti-IL-5 drug with low dose of GC was initiated [2]. After 8 mo, a satisfactory clinical response with normal repeated laboratory tests was achieved except for remaining peripheral neuropathy. …