In asthma, serum periostin may identify patients with Type-2 dependent eosinophilic airway inflammation [1], predict sputum eosinophilia and eosinophilic infiltration of the lung parenchyma [2], and in conjunction with high FeNO identify patients at highest risk of FEV1 decline and asthma exacerbation, regardless of inhaled corticosteroid (ICS) use [3]. Here, POSTN is linked to asthma.