To the editor,
Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease characterized by alveolar surfactant accumulation, progressive dyspnea, and hypoxemic respiratory insufficiency, and in some patients, secondary infections, pulmonary fibrosis, respiratory failure, and death.1 GM-CSF (granulocyte/macrophage colony-stimulating factor) autoantibodies cause aPAP by blocking GM-CSF signaling, which impairs alveolar macrophage functions including surfactant clearance.