Figure 2 - The roles of IL-4 and IL-13 in asthma pathogenesis
Two main drivers of type 2 asthma are IL-4 and IL-13. These cytokines
indirectly and directly lead to airway remodeling by inducing many cell
types and factors, such as DC, epithelial cells, fibroblasts, airway
smooth muscle. IL-4 has mainly central effects related to immunologic
effects in the lymph nodes, while IL-13 mainly acts on tissue cells and
mucus production. Environment factors can trigger the inflammation by
damaging the epithelial barrier. Cycles of inflammation cause repetitive
injury of and repair of the airway wall. IL-4 and IL-13 contribute to
alterations in the epithelium (epithelial shedding, subepithelial
fibrosis). Activated smooth muscle cells contribute airway
hyperresponsiveness, basement membrane thickening and collagen
deposition. Repetitive stimulation of airway epithelium by IL-13 causes
goblet cell hyperplasia and mucus hypersecretion in airway epithelial
cells. Airway remodeling supports the production of pro-inflammatory
mediators.