Cytokines, including IL-4, IL-5 and TNF-α, and chemokines (CCL11 and CCL24) are thought to be involved in eosinophil accumulation and linked to pathophysiology of allergic disease.41, 42, 43, 44 There is also evidence that IL-5 and TNF-α promote eosinophil survival in vitro.45, 46, 47 In addition, CCL11 and CCL24 are important for eosinophil recruitment from the blood to the parenchyma and then into the airway.48 However, the evidence that antibody or drugs targeting these cytokines or chemokine induce resolution of eosinophilic inflammation in vivo is scanty. This evidence concerns the gene IL5 and allergic disease.