The strange case of IL-11

Pulmonary Fibrosis In idiopathic pulmonary fibrosis (IPF), chronic activation of invasive fibroblasts causes fibrotic scar formation in the lungs. Patients with IPF present with progressive breathing difficulty, pulmonary hypertension, and respiratory failure. The pathophysiological mechanisms remain unclear. Interleukin-11 (IL-11) has been shown to participate in kidney and cardiac fibrosis; however, conflicting data suggest IL-11 can either be pro- or antifibrotic. Ng et al. report that in patients with IPF, IL-11 was up-regulated in invasive lung fibroblasts. In vitro and in vivo experiments demonstrated that IL-11 exerted profibrotic effects by driving fibroblast activation. Targeting IL-11 with a neutralizing antibody had therapeutic effects in a mouse model of established pulmonary fibrosis. Sci. Transl. Med. 11 , eaaw1237 (2019).