Quantitation of carcinoembryonic antigen in the lung lining fluid of normal smokers and nonsmokers.

Bronchoalveolar lavage was performed in 47 volunteers: 19 nonsmokers and 28 smokers. Total protein, albumin, immunoglobulins G and A, and carcinoembryonic antigen (CEA) were measured in the concentrated lavage effluent. Although a significant increase (p < 0.001) in the ratio of CEA to total protein recovered from the group of smokers was found, this increase primarily reflected the greater increase that occurred in a subgroup of 7 smokers. However, the increases in lavage CEA correlated weakly (p = 0.096) with smoking history in pack-years, and not at all with plasma CEA concentrations. Results regarding the number of cells recovered and immunoglobulin-to-albumin concentration ratios in these subjects were similar to those reported by others. Thus, CEA was increased in the lavage fluid of a subgroup of otherwise normal young smokers. It is possible that CEA might serve as a useful indicator of future airway disease in certain young smokers.