IL13 and asthma: However, the key difference is that IL-13 majorly participates in the effector phase of type 2 immune responses, thereby affecting the development of several traditional pathophysiological characteristics of asthma owing to the effects it exerts on lung structural cells, including epithelial cells (mucus-secreting goblet cell differentiation and proliferation), SMCs (smooth muscle hypertrophy induction and enhanced contractility), fibroblasts (extracellular matrix [ECM] production), and endothelial cells (vascular remodeling) (8, 104).