Interstitial Lung Disease in Systemic Sclerosis

Abstract

We reviewed the literature concerning pathogenesis, clinical features, diagnosis and treatment of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc). ILD is detectable in approximately 70% of patients at autopsy. Nonspecific interstitial pneumonia (NSIP) is the most common pathologic finding. The earliest phase of ILD in SSc is characterized by microvascular injury and alveolitis. Endothelial lesions, activation of coagulation proteases, especially thrombin, fibroblast proliferation, and differentiation of normal lung fibroblasts to a myofibroblasts phenotype are hallmarks of ILD in SSc. Diagnostic procedures used to detect ILD are chest X-ray, high-resolution computed tomography, bronchoalveolar lavage, lung function tests, and sometimes thoracoscopic lung biopsy. Novel and potentially useful methods to diagnose ILD in SSc are induced sputum and technetium-labeled diethylenetriamine pentaacetate (99mTC-DTPA) clearance time. Cyclophosphamide seems to be relatively effective to treat ILD in the earliest phase, but the effects of other immunosuppressive drugs on the lungs are less convincing.