[A case of pulmonary alveolar proteinosis accompanied with the elevation of CEA (carcinoembryonic antigen) in bronchoalveolar lavage fluid].

A 44-year-old man was admitted with increasing dyspnea and butterfly shadow on his chest roentgenogram. Both the bronchoalveolar lavage and transbronchial lung biopsy (TBLB) led to a diagnosis of pulmonary alveolar proteinosis. CEA level in his bronchoalveolar lavage fluid (BALF) (216.8 ng/ml) was markedly elevated more than that in his serum (50.6 ng/ml). The localization of CEA on TBLB specimen stained by peroxidase-antiperoxidase technique using anti-CEA antibody was investigated and it was found that some alveolar epithelial cells and the material filling the alveoli were positively stained. Functions of alveolar macrophages in BALF were also studied, that is, adherence to glass, cell spreading, the nitroblue tetrazolium reduction, phagocytosis of immunobeads, and the activity of lysosomal enzymes, and found that all of those functions were lower than that of normal smokers. It was suggested that type II alveolar epithelial cells were those which produced and secreted CEA into the alveoli, as they do surfactant-like material in pulmonary alveolar proteinosis, and that the dysfunction of alveolar macrophages was secondary to the overingestion of the proteinaceous material in the alveoli.