[A case of pulmonary alveolar proteinosis with elevated serum angiotensin-converting enzyme activity]

A 45-year-old man with diffuse infiltrates on the chest X-ray film was admitted to the hospital. At first, sarcoidosis was suspected due to the elevated serum angiotensin-converting enzyme (ACE) activity. Transbronchial lung biopsy and bronchoalveolar lavage, however, did not lead to that diagnosis. Pulmonary alveolar proteinosis (PAP) was diagnosed after an open lung biopsy. The diffuse infiltrates on his chest X-ray film diminished spontaneously. Two years later, diffuse infiltrates increased again with an elevated serum ACE activity. In this case, it seemed that the severity of PAP was associated with serum ACE activity. We review the literature on the relationship between serum ACE activity and dysfunction of alveolar macrophages in PAP.