IL4 and asthma: Finally, asthma-related Th2 cytokines such as IL-4, IL-5, and IL-13 can induce EGFR expression (Wills-Karp, 2004), while cytokines produced by activated eosinophils such as IL-3 and IL-5 can induce TGF-α production by epithelial cells and subsequently induce mucins production through EGFR signaling (Burgel et al., 2001).