Pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare syndrome associated with abnormal accumulation of (lipo-)protein material in the alveoli, often due to decreased granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling activity, dysfunction of alveolar macrophages, or abnormal surfactant metabolism. Autoimmune PAP accounts for 90% of all cases of PAP and has a prevalence of 7 - 10 cases per million in the general pop­ulation. The aim  of the study is to summarize current approaches to the diagnosis and treatment of pulmonary alveolar proteinosis based on recent clinical guidelines. Conclusion. Nonspecific clinical presentation, radiographic findings, and normal routine laboratory results often lead to misdi­agnosis of PAP and prolonged path to the diagnosis. Serum testing for GM-CSF autoantibodies has revolutionized the diagnosis of autoimmune PAP, making lung biopsy unnecessary in most cases. Therapy for PAP has evolved significantly in recent years, and European Respiratory Society (ERS) guidelines (2024) proposed the first clear, hierarchical treatment algorithm. Whole lung lavage, historically a first-line treatment, should now be considered alongside inhaled GM-CSF, based on numerous high-quality studies published in recent years. The ERS guidelines clarify the treat­ment sequence for refractory autoimmune PAP, with rituximab considered a third-line treatment and plasmapheresis a fourth-line treatment.