BALF N-acetylglucosaminidase and beta-galactosidase activities in idiopathic pulmonary fibrosis.

The lysosomal enzymes N-acetylglucosaminidase (N-ACGA) and beta-galactosidase (beta-gal) are involved in cellular collagen metabolism and may, therefore, be markers of fibrosis in idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis (IPF). N-ACGA and beta-gal were analyzed in the bronchoalveolar lavage fluid (BALF) of patients with the histologic pattern of usual interstitial pneumonia (UIP, n=10) and controls (n=9). Cellular distribution in BALF as well as the concentration of TGF-beta a well-known mediator of fibroblast matrix deposition were correlated to the enzyme activities in both groups of patients. We found that both, N-ACGA (UIP: 25.2 nmol/l s +/- 3.4; controls: 73 nmol/l s +/- 1.3) and beta-gal (UIP: 4.7 nmol/l s +/- 0.5; controls: 2.4 nmol/l s +/- 0.3) were elevated significantly in BALF of patients with IPF compared to that of control patients (P<0.003). This increase was paralleled by an increase in neutrophils (IPF: 17.9% +/- 21.8; controls: 5.4% +/- 6.3; P=0.03) and eosinophils (IPF: 2.0% +/- 1.5; controls: 0.2% +/- 0.45; P=0.002) in BALF fluid. In addition, N-ACGA activity correlated closely with lung function (FVC, TLC, and DLCO), transforming growth factor-beta (TGF-beta) in BALF (r=0.77, P=0.008) and activated lymphocytes (r=0.66, P=0.0021). Our findings suggest that measurement of lysosomal enzymes such as N-ACGA may represent a useful indicator of fibrotic activity in IPF.