AHR and asthma: According to recent studies, IL-17 is an important cytokine for the pathogenesis of asthma and its exacerbation in at least some asthmatic patients, especially those with severe asthma (Chakir et al. 2003; Iwanaga and Kolls 2019), the effect of IL-17 on asthma seems to be dose dependent with low doses increasing and high doses decreasing the AHR (Kinyanjui et al. 2013).