Importance of the field: Pulmonary alveolar proteinosis (PAP) is a rare disease in which the abnormalities in surfactant metabolism are caused most often by impairments of GM-CSF pathway at different levels in different disease subsets (congenital, secondary, acquired/idiopathic) and for which there are only few, costly invasive therapeutic methods.

Areas covered in this review: This review discusses these impairments, and their pathogenic and clinical consequences along with potential corrective therapies such as exogenous inhaled GM-CSF.

What the reader will gain: Among the PAP disease subsets, in autoimmune PAP the GM-CSF autoantibodies play a major role in disease pathogenesis and their deleterious pulmonary effects can be blocked efficaciously with inhaled GM-CSF.

Take home message: In PAP correction of the abnormalities of the GM-CSF pathway represent a plausible approach demonstrated to be efficacious also in the case of inhaled GM-CSF used for autoimmune PAP.