This article appears in the following Rheumatology issue: Update in systemic sclerosis [View the issue table of contents]
Histopathology and bronchoalveolar lavage
1Division of Rheumatology & Immunology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA and 2Interstitial Lung Disease Unit, Royal Brompton Hospital, London, UK.
Correspondence to: R. M. Silver, Medical University of South Carolina, 96 Jonathan Lucas Street, Suite 912, Charleston SC 29425, USA. E-mail: silverr{at}musc.edu
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Abstract |
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Although neither lung biopsy nor bronchoalveolar lavage (BAL) is recommended for routine clinical use in patients with SSc, studies employing lung biopsy material and BAL fluid (BALF) have provided insight into the pathogenesis of scleroderma-associated interstitial lung disease (SSc-ILD). Most often, SSc-ILD is classified as a non-specific interstitial pneumonia, with abundant myofibroblasts and evidence of both epithelial cell and endothelial cell injury. Recently, SSc-ILD fibroblasts have been shown to express reduced levels of the caveolin-1 protein which, in turn, may lead to activation of the signalling molecules associated with increased collagen production and overexpression of 
-smooth muscle cell actin (-SMA). BALF often contains increased numbers of inflammatory cells as well as myofibroblasts expressing -SMA. Analysis of BALF suggests an imbalance between pro-fibrotic and anti-fibrotic factors, e.g. an overabundance of TGF-β, connective tissue growth factor (CTGF), PDGF, leucotriene B4, etc. and in some cases a deficiency of hepatocyte growth factor, 15-hydroxyeicosatetraenoic acid (15-HETE), lipoxin A, etc. Until the pathogenesis is fully understood, lung biopsy and BAL will remain useful research tools to better understand the inflammatory and fibrosing processes that underlie SSc-ILD.
KEY WORDS: Scleroderma, Interstitial lung disease, Lung biopsy, Lung histopathology, Myofibroblast, Bronchoalveolar lavage, Cytokines, Growth factors
Submitted 1 May 2008; Accepted 18 June 2008