Clinical aspects of lung involvement: Lessons from idiopathic pulmonary fibrosis and the scleroderma lung study

Interstitial lung disease (ILD) occurs frequently among patients with systemic slcerosis (SSc) and accounts for significant morbidity and mortality. SSc-ILD resembles idiopathic pulmonary fibrosis (IPF) in many respects; each is characterized by a restrictive ventilatory defect that results from an active fibrosing process in the lung interstitium, and each is characterized by ground glass opacification on high resolution computed tomography (HRCT) and inflammatory cells in bronchoalveolar lavage fluid (BALF). Differences in the classification of lung histopathology are noted frequently and may account for some of the difference in outcome for patients with SSc-ILD and IPF. Optimal treatment of SSc-ILD remains to be determined, but cyclophosphamide has been reported to be effective in a number of case series. A randomized controlled trial, the Scleroderma Lung Study (SLS), will be completed in 2005; the outcome of the SLS should define the efficacy of daily oral cyclophosphamide for SSc-ILD patients with alveolitis defined by BALF and HRCT.