LAUSR

Hypereosinophilic syndrome (HES), a rare systemic disease, was first described in 1968. As a subtype of HES, idiopathic hypereosinophilic syndrome (IHES) is defined as hypereosinophilia of unknown cause, excluding tumor, infection, allergy, and immune system disease. In most cases, more than 1 organ is affected in patients with IHES. The first-line drug for the treatment of IHES is glucocorticoid, which is effective for both hypereosinophilia and clinical manifestations. However, when the outcome of hormone treatment is unsatisfactory, immunosuppressive or antineoplastic agents can also be administered. Due to the low incidence of IHES, there is currently a lack of large-scale retrospective studies of the disease. We aimed to identify factors predictive of prognosis and determine the endpoint eosinophil (EOS) count after pharmacological therapy and the time at which a change of therapy should be considered following the failure of hormone treatment.