PROBLEM TO BE SOLVED: To provide a method for increasing the one second dose (FEV1) of an asthma patient. SOLUTION: An asthma patient is administered with an effective amount of benralizumab or an antigen-binding fragment thereof. [Selection diagram] None【課題】喘息患者の1秒量(FEV1)を増加させる方法の提供。【解決手段】喘息患者に有効量のベンラリツマブまたはその抗原結合フラグメントを投与する。【選択図】なし