Out of breath: GM-CSFRα mutations disrupt surfactant homeostasis

Pulmonary alveolar proteinosis (PAP) is a rare disorder in which surfactant homeostasis in the lung is impaired, causing respiratory distress and, in severe cases, respiratory failure. Most cases of PAP are associated with the formation of autoantibodies against the cytokine granulocyte/macrophage colony- stimulating factor (GM-CSF), which is required for normal surfactant homeostasis and lung function. New studies now identify three patients in whom PAP was caused by mutations in the gene encoding the ligand-binding α chain of the GM-CSF receptor.