IL-9 and Lung Fibrosis

Interleukin (IL)-9 is a cytokine with pleiotropic activities that has been implicated in the pathogenesis of asthma and is shown in the article by Arras and colleagues as having the capacity to modulate the development lung fibrosis. IL-9 was discovered independently as a growth factor for activated T cells (1) and subsequently for mast cells (2). Cloning of the mouse (3) and human (4) IL-9 cDNAs revealed that they encoded polypeptides 144 amino...