IL5 and asthma: Asthma exacerbation is often attributed to the imbalance of Th1/Th2, that Th2 cells secrete Th2-type cytokines [interleukin (IL)-4, IL-5, and IL-13] to amplify type 2 inflammation while Th1 cells secrete Th1-type cytokines [interferon (IFN)-γ, IL-2, lymphotoxin (LT)-α, and tumor necrosis factor (TNF)-α] to confine type 2 inflammation, but mediate type 1 inflammation (Foster et al., 2017; Mukherjee and Nair, 2018).