Since autoantibodies to GM-CSF cause defects in chemotaxis, adhesion, phagocytosis, microbicidal activity and phagolysosome fusion of alveolar macrophages [51], patients with PAP are at risk for infections from a variety of respiratory microorganisms including fungal species [25,44,58,59]. This evidence concerns the gene CSF2 and pulmonary alveolar proteinosis.