Two cases of pulmonary alveolar proteinosis with increase of serum CEA

Two cases of pulmonary alveolar proteinosis with increased serum CEA were reported. In both cases, the clinical diagnosis of pulmonary alveolar proteinosis was confirmed by transbronchial lung biopsy (TBLB). Immunohistochemical study of the lung biopsy specimen showed that CEA staining was present in the region of alveoli where type II alveolar epithelial cells proliferate. It was suggested that proliferative type II cells produced CEA in pulmonary alveolar proteinosis. The study of cell surface markers in their bronchoalveolar lavage fluid (BALF) revealed increase of CD8 and Leu7 positive cells and decrease of CD4 positive cells. In the case 2, there was significant increase of B lymphocytes marker positive cells. These results suggested that there may be abnormal regulation of both T and B lymphocytes and NK cells, leading to dysfunction of the pulmonary alveolar macrophage in pulmonary alveolar proteinosis.