EXHALED NITRIC OXIDE AS PREDICTOR MARKER OF INTERSTITIAL LUNG DISEASE AND FIBROSIS

Endothelial dysfunction and activation of the immune system are the two major pathophysiological mechanisms responsible for the fibrosis of the skin and internal organs in systemic sclerosis. The diffuse interstitial lung disease (PID) has become the main cause of the disease mortality. Pulmonary inflammation is the result of activation of the immune system, which stimulates the inducible NO synthase and increases cellular production of nitric oxide (NO). Increasing alveolar NO concentration (CANO) was significantly correlated with the severity of the PID in patients with systemic sclerosis. Increased CANO is related to the inducing capacity of serum from patients on lung fibroblast proliferation and their differentiation into myofibroblasts, linking active alveolitis to cell mechanism of pulmonary fibrosis in the disease. Alveolar nitric oxide concentration has a strong predictive value on the deterioration of the PID within a 3-year follow-up. These patients could then receive early appropriate treatment such as immunosuppressive medication.