Inhaled GM-CSF for Pulmonary Alveolar Proteinosis

Pulmonary alveolar proteinosis is a disease characterized by abnormal accumulation of surfactant in the alveoli. Most cases are autoimmune and are associated with an autoantibody against granulocyte–macrophage colony-stimulating factor (GM-CSF) that prevents clearing of pulmonary surfactant by alveolar macrophages. An open-label, phase 2 study showed some therapeutic efficacy of inhaled recombinant human GM-CSF in patients with severe pulmonary alveolar proteinosis; however, the efficacy in patients with mild-to-moderate disease remains unclear.