BAL SURFACTANT PROTEIN-A AND CLARA CELL 10-KDA PROTEIN-LEVELS IN HEALTHY-SUBJECTS

Lung surfactant protein A (SP-A) and Clara cell 10-kDa protein (CC10) are the most abundant proteins produced locally in the lower respirato ry tract, as assessed in bronchoalveolar lavage (BAL) analysis. Howeve r, it is not known what factors influence SP-A and CC10 levels in BAL fluids, and the relationship between SP-A and CC10 levels in BAL fluid s has been unclear. We measured SP-A and CC10 concentrations in BAL fl uids from 11 healthy nonsmokers and 12 healthy smokers by enzyme-linke d immunosorbent assays using specific antibodies. Mean SP-A and CC10 l evels in BAL fluids of healthy smokers were significantly lower than t hose of healthy nonsmokers. SP-A values correlated significantly with CC10 and phospholipid values in BAL fluids. CC10 values tended to corr elate with phospholipid values in BAL fluids. On BAL examinations usin g three 50-ml aliquots, the mean SP-A level in the second lavage was 2 .0-fold and 2.4-fold, respectively, of that in the first and third lav ages, and the mean CC10 level in the first lavage was 5.0-fold and 5.6 -fold, respectively, of that in the second and third lavages. We concl ude that BAL fluid SP-A and CC10 levels are influenced by the BAL meth ods and by cigarette smoking. There is a significant positive correlat ion between SP-A and CC10 values in BAL fluids of healthy subjects.