IL4 and asthma: Dupilumab is a fully human IgG4 monoclonal antibody capable of suppressing the biological actions of IL-4 and IL-13 through selective binding to IL-4Rα, shared by these two cytokines for the activation of their receptor mechanisms [166]; this drug is effective in severe asthmatics with at least 150 eosinophils per microliter of blood and / or at least 25 parts per billion (ppb) of FeNO and has therapeutic effects including rapid and relevant improvements in asthma exacerbations, symptom control, airflow limitation, lung hyperinflation and OCS intake [167,168,169].