CXCL8 and viral infectious disease: The induction of TSLP and IL-8 in epithelial cells in response to viral stimulation, and their interaction with Th2 cytokines in the microenvironment—particularly during viral infections in asthma—should be a focus of attention for clinicians, especially in severe asthma cases where the selection of appropriate biologic agents should be guided by the underlying pathophysiological condition.