Sequential granulocyte-macrophage colony-stimulating factor inhalation after whole-lung lavage for pulmonary alveolar proteinosis: A report of five intractable cases

Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease characterized by the excessive accumulation of surfactant proteins within the alveolar spaces and by higher titers of autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) in the serum and bronchoalveolar lavage fluid. The antibodies inhibit the maturation and phagocytosis of alveolar macrophages. Although the standard therapy for aPAP has been whole-lung lavage (WLL), this procedure is invasive and needs to be repeated for several years. GM-CSF inhalation therapy is a new procedure for treating aPAP and can induce remission with less invasiveness, although it is generally less effective in severe cases. We evaluated five cases with remarkable improvement by using sequential GM-CSF inhalation therapy after WLL; however, the treatment failed when this therapy preceded WLL. Therefore, sequential GM-CSF inhalation after WLL may reinforce the efficiency of WLL in patients with severe aPAP.