Pulmonary alveolar proteinosis and granulocyte/macrophage-colony stimulating factor (GM-CSF) inhalation

Abstract

ABSTRACTIntroduction: Pulmonary alveolar proteinosis (PAP) is a rare lung disease characterized by surfactant accumulation within pulmonary alveoli, resulting in progressive respiratory insufficiency. Approximately 90% of PAP patients have autoimmune PAP (aPAP), which is associated with high levels of autoantibodies against granulocyte/macrophage-colony stimulating factor (GM-CSF). These autoantibodies neutralize the GM-CSF activity and are thought to cause the disorder by impairing alveolar macrophage-mediated surfactant clearance. aPAP has been commonly treated by whole-lung lavage, a procedure requiring general anesthesia. Based on the molecular pathogenesis of aPAP, GM-CSF inhalation has been investigated as a novel therapy since 2000.Areas covered: This manuscript outlined the clinical and pathological features of PAP and reports on GM-CSF inhalation treatment.Expert opinion: GM-CSF inhalation is a promising treatment for aPAP, and is feasible in outpatient settings. To obtain the approval of regulatory authorities, chronic toxicity studies and randomized control trials will be required. Standard assay kit for detecting anti-GM-CSF antibody should be developed. GM inhalation could be tested in other pulmonary diseases such as acute respiratory distress syndrome. The combination treatment of whole-lung lavage and subsequent GM-CSF inhalation therapy will be a potential measure to enable nebulized GM-CSF to reach the peripheral alveoli.