TENASCIN IS INCREASED IN EPITHELIAL LINING FLUID IN FIBROTIC LUNG DISORDERS

Tenascin is an extracellular matrix glycoprotein increased immunohisto chemically in tumorous and fibrotic lung tissues as demonstrated by im munohistochemistry. We hypothesized that in bronchoalveolar lavage (BA L) fluid also the tenascin concentration would be elevated in patients with various fibrotic lung disorders. The aim of our study was to inv estigate whether BAL fluid tenascin would be increased compared with s erum tenascin in patients with usual interstitial pneumonia (UIP), sar coidosis, and extrinsic allergic bronchioloalveolitis. For this purpos e BAL fluid was collected from five patients with UTP, 12 patients wit h sarcoidosis, five patients with extrinsic allergic bronchioloalveoli tis, and six patients in a control group. BAL fluid and serum tenascin concentrations were detected by the enzyme immunoassay method. The BA L fluid results were expressed as tenascin concentrations in the epith elial lining fluid (ELF), as estimated by the urea method. The ELF ten ascin concentration was increased in the patients with fibrotic lung d isorders relative to the control group (mean 0.12 mu g/ml) and was hig hest in the UIP group (mean 5.72 mu g/ml) and sarcoidosis group (mean 4.76 mu g/ml). It is concluded that the tenascin concentration in the ELF is increased in patients with UIP, sarcoidosis, and extrinsic alle rgic bronchioloalveolitis, suggesting active synthesis of tenascin in the lower respiratory tract in such disorders.