RESUMO
BACKGROUND: Interstitial lung disease is a well-recognized prognostic factor in systemic sclerosis (SSc). As the prognosis in nonspecific interstitial pneumonia (NSIP) has been described to be better in collagen vascular disorders compared to the idiopathic forms, we hypothesize that the mechanisms of repair and remodeling are different between these 2 forms of the disease. OBJECTIVES: To compare the mechanisms of repair and remodeling between SSc-associated NSIP and the idiopathic form, its impact on pulmonary function tests and survival rates. METHODS: We analyzed 18 biopsies from patients with NSIP associated with SSc and 22 with idiopathic NSIP and compared the epithelial and vascular densities as well as vascular activity. RESULTS: Epithelial cell density was lower in SSc-NSIP when compared with idiopathic NSIP (p < 0.0001). Type II pneumocytes and Clara cells were reduced in idiopathic NSIP (p = 0.02). A decrease in microvessel density was found in SSc-NSIP compared to idiopathic NSIP (p < 0.0001). The vascular activity measured by VCAM expression was higher in NSIP-SSc when compared to the idiopathic group (p < 0.0001). The DLCO/VA in SSc-NSIP was more compromised. A direct association between vascular density and DLCO/VA was found (p = 0.02). There was no difference in the survival rate between the 2 groups after a follow-up of 36 months. CONCLUSIONS: Alterations in the epithelium and vasculature seem to differ in the pathogenesis of SSc-NSIP when compared to the idiopathic form of the disease. Further studies may be required to assess the significance of these findings and explore if they can provide prognostic and/or treatment information.
