The dysfunction of ciliated and secretory cells is observed in both asthma types; however, in Th2-high asthma the key early activators released by epithelial cells in response to allergens are IL-25, IL-33, and thymic stromal lymphopoietin (TSLP), whereas in Th2-low asthma, TNF-α, IL-6, IL-8, and IL-1β are the main inflammatory mediators released in response to environmental factors [45]. This evidence concerns the gene TNF and asthma.