IL22 and asthma: Inhalation allergens, especially house dust mite (HDM), are mainly related to asthma and allergic rhinitis (Gandhi et al., 2013), and recent studies have reported that IL-22, predominantly secreted by T helper type 17 (Th17) cells, is highly expressed in various infectious and inflammatory diseases, especially childhood allergic rhinitis and asthma (Farfariello et al., 2011; Tsuji et al., 2012a).