Isolation of mycobacteria in patients with pulmonary alveolar proteinosis.

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by accumulation of proteinaceous material in the alveoli of affected individuals. Pulmonary infections appear to develop with increased frequency in these patients. The increased rate of infection has been attributed to immunologic aberrations, such as impaired alveolar macrophage function, particularly when uncommon pathogens are involved. Among those pathogens, Nocardia asteroides and Mycobacterium tuberculosis have appeared most often in case reports in the literature. Mycobacterium avium-intracellulare (MAI) has rarely been isolated in these patients. We report an unusually high incidence of MAI isolation from lavage fluid in 8 of 19 consecutive patients who underwent therapeutic lung lavage for relief of symptomatic PAP, and summarize the available literature on isolation of potential respiratory pathogens in PAP.