Abstract:Objective To explore the expressions and significance of serum Krebs von den Lungen-6 (KL-6),CC chemokine ligand 18(CCL-18) and microRNA-21 (miR-21) in patients with idiopathic pulmonary fibrosis (IPF) and their associations with pulmonary function and disease severity. Methods Sixty patients with IPF treated from March 2014 to June 2018 were selected as IPF group,and 60 health examiners were served as control group at the same time.The serum levels of KL-6,CCL18 were detected by ELISA,and miR-21 were detected by real-time fluorescence quantitative PCR,respectively in two groups to observe the changes of the above-mentioned molecular markers.The relationship between their levels and the pulmonary function indexes ［forced vital capacity (percentage of predicted value),FVC%pred and diffusing capacity for carbon monoxide ( percentage of predicted value),DLco%pred］ were analyzed.The levels of KL-6,CCL18 and miR-21 were compared in the patients with stable and acute exacerbation of IPF. Results The levels of serum KL-6,CCL18 and miR-21 in IPF group were significantly higher than those in control group (P<0.01),and their expression levels were negatively correlated with FVC%pred (KL-6:r=-0.47,P<0.01;CCL18:r=-0.53,P<0.01;miR-21:r=-0.50,P<0.01) and DLco%pred (KL-6:r=-0.35,P<0.01;CCL18:r=-0.48,P<0.01;miR-21:r=-0.38,P<0.01),respectively.Compared with the stable patients,the serum levels of KL-6,CCL18 and miR-21 were further increased in patients with acute exacerbation of IPF (KL-6:P=0.011,CCL18:P=0.049,miR-21:P=0.033). ConclusionThe serum levels of KL-6,CCL18,and miR-21 in IPF patients are obviously higher than those in health persons,and their levels are correlated with pulmonary function parameters and the severity of the disease,which can be used as biomarkers for evaluating the development and prognosis of the patients with IPF.