Our new understanding of pulmonary alveolar proteinosis: What an internistneeds to know

Pulmonary alveolar proteinosis (PAP; the accumulation of surfactant lipids and proteins in the alveoli) has a number of infectious and environmental c auses but is usually idiopathic. The clinical presentation of PAP is nonspe cific; thus, the diagnosis is frequently missed, leading to inappropriate t herapy and unnecessary morbidity. Recent advances suggest that a deficiency in granulocyte-macrophage colony-stimulating factor (GM-CSF) activity may lead to this surfactant accumulation. Anti-GM-CSF antibodies have been foun d in PAP patients, fueling speculation that PAP may be an autoimmune diseas e. These findings are being translated into novel forms of therapy.