IL17A and asthma: The second peak is usually adult-onset/old age asthma, also known as non-T2 (T2 low) and is neutrophilic and paucigranulocytic, corticosteroids less responsive or resistant, hence also known as severe asthma, and inflammation is driven through T helper 1 (Th1), T helper 17 (Th17) cells, neutrophils, and IL-1ß, IL-8, IL-16, IL-17A/F, IFN-γ, and TNF-α.