IL11 and idiopathic pulmonary fibrosis: In a clinical trial, it was found that the expression of IL-11 and IL-11RA in the pulmonary artery, pulmonary parenchyma, serum, and alveolar lavage fluid of patients with idiopathic pulmonary fibrosis (IPF) and PH was higher compared with the control group, and was prolonged than in patients with IPF but without PH.