IL4R and asthma: The current add-on treatment options for severe asthma are long-acting muscarinic antagonist (LAMA), leukotriene modifier, low dose azithromycin, and low dose oral corticosteroids (OCS), and biological drugs such as anti-IgE, anti-IL-5/IL-5R, or anti-IL-4R for type 2 severe asthma (1, 3).