Hypereosinophilia under dupilumab therapy in CRSwNP – Different faces of a hematologic side effect?

Introduction An increase in blood eosinophil count (BEC) is a common side effect observed during the first months of anti-IL4/13 dupilumab treatment. The accumulation of blood eosinophils is likely caused by inhibition of eosinophil migration to peripheral tissues due to downregulation of adhesion molecules and continued eosinophilopoiesis in the bone marrow. We sought to review events of hyperosinophilia (BEC>1500/μL) in CRSwNP patients treated with dupilumab in our clinic.