Systemic sclerosis and idiopathic interstitial pneumonia: histomorphometric differences in lung biopsies

Author(s)

Edwin Roger Parra ^[1] ; Leandro Hideki Otani ^[2] ; Erika Franco de Carvalho ^[3] ; Alexandre Ab'Saber ^[4] ; Vera Luiza Capelozzi ^[5]

Affiliation

^[1] University of São Paulo. School of Medicine - Brasil

^[2] University of São Paulo. School of Medicine. Hospital das Clínicas - Brasil

^[3] University of São Paulo. School of Medicine - Brasil

^[4] University of São Paulo. School of Medicine - Brasil

^[5] University of São Paulo. School of Medicine. Department of Pathology - Brasil

• Document type: Journal article
• Source: Jornal Brasileiro de Pneumologia; v. 35, n. 6, p. 529-540, 2009-06-00.

Abstract

OBJECTIVE: The aim of this study was to examine the parenchymal and extracellular matrix remodeling process in two histologic patterns-nonspecific interstitial pneumonia (NSIP) and usual interstitial pneumonia (UIP)-in cases of idiopathic and sclerosis/systemic sclerosis (SSc)-associated interstitial pneumonia. METHODS: We examined 15 cases of idiopathic NSIP, 10 cases of idiopathic UIP, 5 cases of SSc-UIP and 9 cases of SSc-NSIP. In the lung parenchyma, epithelial cells, endothelial cells and myofibroblasts were evaluated by immunohistochemical staining, whereas histochemical staining was used in order to evaluate collagen/elastic fibers in the extracellular matrix. RESULTS: The percentage of surfactant protein A-positive epithelial cells was significantly greater in idiopathic NSIP than in SSc-NSIP, as well as being greater in idiopathic UIP than in SSc-UIP. Idiopathic NSIP and idiopathic UIP presented significantly higher immunoexpression of alpha smooth muscle actin in myofibroblasts than did SSc-NSIP and SSc-UIP. The percentage of CD34 endothelial cells in the pulmonary microvasculature was significant lower in idiopathic UIP than in SSc-UIP. The density of collagen fibers was significantly greater in idiopathic NSIP and idiopathic UIP than in SSc-NSIP and UIP. In contrast, the elastic fiber density was significantly lower in idiopathic UIP than in SSc-UIP. CONCLUSIONS: Increased collagen synthesis, destruction of elastic fibers, high myofibroblast proliferation and poor microvascularization might represent a remodeling process found in idiopathic interstitial pneumonia, whereas the reverse might represent a repair process in SSc-associated interstitial pneumonia. (AU)