2008). Pendrin expression is upregulated after IL-4 stimulation in cultured airway epithelia (Pedemonte et al. 2007) and disease tissues, such as those from asthma, COPD, and rhinitis patients (Kuperman et al. 2005; Lewis et al. 2008; Ishida et al. 2012). Moreover, patients with pendrin mutations had a tendency to be resistant to asthma (Nakao et al. 2008). Here, SLC26A4 is linked to chronic obstructive pulmonary disease.