Background Systemic sclerosis (SSc) is an autoimmune disease of unknown etiology which affects the whole body. Extensive fibrosis of the skin and internal organs (including lungs – interstitial lung disease (ILD)) are typical for SSc. However the level of NO in exhaled air has been limited diagnostic value. Previous studies suggest that it seems to be a good predictor of the involvement of pulmonary tissue [1,2,3]. Some authors suggest it can be even a marker of early lung involvement in the disease.
Objectives To measure the level of NO in exhaled air in a group of patients with SSc and to compare the concentrations of NO with pulmonary function tests and standard parameters assessed in patients with SSc.
Methods Seventeen patients were enrolled in the study, of which 13 fulfilled the ACR criteria for SSc. Four patients presented typical symptoms of SSc: Raynaud phenomenon, capillaroscopic pattern, presence of ANA and specific autoantibodies (Scl-70, ACA) and ILD (3 cases), but had no skin changes. The necessary data concerning the disease activity were collected including blood tests, capillaroscopy and modified Rodnan skin score (mRSS). All the patients included in the study, underwent lung function tests (spirometry, diffusion capacity DLCO). The measurements of exhaled NO (FeNO, fraction of exhaled nitric oxide at a flow of 50 ml/s) were done using NIOX analyser (Aerocrine). The diagnosis of pulmonary involvement was based on clinical examination, x-ray pictures of the chest or, if there were indications, on high resolution computer tomography (HRCT). The statistical analysis was performed by using the Statistica 9 software.
Results The study involved 17 pts (3 men, 14 women); mean age 52.4±12.37 years; mean disease duration 3.0±2.91 years. The measured concentrations of exhaled NO range from 0.8 to 28.2 ppb (parts per billion). We found correlations of NO neither with pulmonary function tests nor indicators of disease status such as capillaroscopic pattern of nailfold capillaries, ESR, C-reactive protein serum concentration, presence of digital ulcers and the value of mRSS. No statistically significant correlation was found between exhaled NO levels and the presence of ILD.
Conclusions The results of this small observational study do not confirm earlier suggestions about the predictive value of NO concentrations in exhaled air.
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Tiev KP, Cabane J, Aubourg Fet al. Severity of scleroderma lung disease is related to alveolar concentration of nitric oxide.Eur Respir J.2007 Jul;30(1):26-30.
Disclosure of Interest None Declared