Tohoku J. Exp. Med., 2018 November, 246(3)

Association between Pepsin in Bronchoalveolar Lavage Fluid and Prognosis of Chronic Fibrosing Interstitial Lung Disease

YOULIM KIM,1,2 YEON JOO LEE,2,3 YOUNG-JAE CHO,2,3 HO IL YOON,2,3 JAE HO LEE,2,3 CHOON-TAEK LEE2,3 and JONG SUN PARK2,3

1Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea
2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
3Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea

Chronic fibrosing interstitial lung disease (ILD)s are characterized by chronic progressive fibrosis of lung which include idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and connective tissue disease-associated interstitial lung disease (CTD-ILD). IPF is an irreversible fibrotic lung disease which results in respiratory failure. Although NSIP and CTD-ILD can be improved or stable by treatment with corticosteroid or immunosuppressant, some of them progress to fibrotic lung diseases. Aspiration of gastric contents is suggested as an aggravating factor of ILDs. We measured pepsin, a marker of gastric aspiration, in bronchoalveolar lavage (BAL) fluid of chronic fibrosing ILD patients to evaluate the association between BAL fluid pepsin and prognosis of chronic fibrosing ILDs. Patients with chronic fibrosing ILDs, who underwent bronchoscopy between December 2010 and April 2015 were prospectively enrolled. Pepsin levels were measured using a commercial ELISA kit. Clinical characteristics, lung function data, and mortality were analyzed. Fifty-one patients with chronic fibrosing ILDs were enrolled (26 with IPF, 15 with NSIP, and 10 with CTD-ILD). Pepsin levels in BAL fluid were 69.87 ± 74.16 ng/mL in IPF, 110.68 ± 94.93 ng/mL in NSIP, and 101.87 ± 88.44 ng/mL in CTD-ILDs. There were no statistically significant differences in BAL fluid pepsin levels among patients with the different chronic fibrosing ILDs. In multivariate regression analysis, higher BAL pepsin levels were associated with higher mortality (adjusted odds ratio [aOR] = 1.021, p = 0.025). BAL fluid pepsin may be used as a prognostic marker for predicting mortality in chronic fibrosing ILD patients.

Key words —— aspiration; bronchoalveolar lavage fluid; interstitial lung disease; pepsin; pulmonary fibrosis

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Tohoku J. Exp. Med., 2018, 246, 147-153

Correspondence: Jong Sun Park, M.D, Ph.D., Seoul National University Bundang Hospital, 82, Gumi-ro 173 Beon-gil, Bundang-gu, Seongnam, Gyeonggi-do 13620, Republic of Korea.

e-mail: jspark.im@gmail.com