IL13 and asthma: In a recent study Ahdieh and colleagues have clearly demonstrated Th1 and Th2 cytokines have distinct activities in lung epithelial cells that are consistent with the role of these cytokines in lung inflammation (e.g. asthma) In particular, IL-4 and IL-13 disrupt epithelial barrier function and wound healing, both of which would be expected to exacerbate inflammation.