In conclusion, inhibition of IL-4 and IL-13, and to a lesser degree inhibition of IL-13 alone, may benefit patients with T2 high asthma, such as those with elevated FeNO levels, elevated blood eosinophils (≥300 cells/μL) or sputum eosinophils (≥3%), and/or elevated periostin. This evidence concerns the gene IL13 and asthma.