The observed increases in eosinophil blood counts observed in dupilumab-treated patients with asthma, chronic rhinosinusitis, and atopic dermatitis (25) may be due to reduced CCL26 release from the airway epithelium disrupting the chemoattractant signal required for blood eosinophils to migrate to the tissue, in turn resulting in increased levels of blood eosinophils. Here, CCL26 is linked to chronic rhinosinusitis.