Abstract

The recovery of protein and two specific surfactant lipids, phosphatidylcholine and phosphatidylglycerol, from bronchoalveolar lavage fluid is altered in chronic and acute non-granulomatous interstitial lung disease. This study set out to determine whether the same is true for patients with sarcoidosis. The median value for recovery of protein from lavage fluid was significantly higher in 21 patients with sarcoidosis than in 19 normal subjects (18 v 11 mg), while the median value for phospholipid recovery was significantly lower (4 v 1.7 mg). There were no changes in the proportions of phosphatidylcholine and phosphatidylglycerol. In addition, significantly less of the neutral lipid, cholesterol, was recovered (3.2 v 1.5 mg). The combined values of three biochemical measurements, non-phospholipid polar lipid, non-polar lipid, and protein, correctly classified all 40 subjects in our series; in a further group of nine normal subjects and 11 patients with sarcoidosis it allowed all but one normal subject to be classified correctly. These results are discussed in terms of alterations in epithelial cell function in interstitial disease.