IL13 and asthma: However, the current treatment for severe asthma is focused predominantly on targeting Th2/eosinophilic inflammation, with sputum eosinophil counts and exhaled nitric oxide fraction (FENO) as a therapy guide, and therapies primarily targeting Th2 inflammation (e.g., IL-5, anti-IgE, anti-IL-4/IL-13) as treatment options (17).