IL4 and chronic obstructive pulmonary disease: Since the IL‐4/IL‐13 axis induces the migration and maturation of cord and peripheral blood eosinophil progenitors (CD34+ CD45+) but does not influence the migration of committed or mature cells [11], IL‐18 activity on eosinophils maturation could provide a possible mechanism linking COPD and EoE to the absence of blood eosinophilia during dupilumab treatment.