AHR and asthma: This is in line with a recent analysis suggesting that β2-receptor polymorphisms do not affect the therapeutic response to LABA in patients with asthma.46 Our observation that the majority of patients with mild asthma developed an increase in AHR following salmeterol monotherapy suggests a susceptible subpopulation of patients which cannot be identified by β2-receptor polymorphisms or other clinical characteristics obtained in our study.