Utility of fractional exhaled nitric oxide in interstitial lung disease

The majority of interstitial lung diseases (ILDs) develop rapidly and are associated with a poor prognosis. Therefore, new noninvasive markers are needed to guide the classification and prognostication of ILD. We enrolled 95 patients with ILD, including dermatomyositis-associated ILD (n = 69), Sjogren's syndrome-associated ILD (n = 7), mixed connective tissue disease-associated ILD (n = 9), idiopathic pulmonary fibrosis (n = 5) and hypersensitivity pneumonitis (n = 5), 82 patients with connective tissue disease but without ILD as well as 24 healthy controls, then evaluated fractional exhaled nitric oxide (FeNO50; 50 ml s(-1)) (Bisenkov et al 2006 Vestn. Khir. Im. I. I. Grek. 165 9-14), pulmonary function and high-resolution computed tomography (HRCT) scores. Blood samples were analyzed and bronchoalveolar lavage fluid parameters were measured. There was no significant difference in FeNO50 values between different subgroups of ILD patients or between different subgroups of ILD patients and healthy controls. However, we found that FeNO50 was negatively correlated with the HRCT score and positively correlated with forced vital capacity. FeNO50 values did not play a clinical role in the diagnosis, differential diagnosis or prognostication of ILD.