Pulmonary alveolar proteinosis.

Area of Science:

• Pulmonary Medicine
• Immunology
• Genetics

Background:

• Pulmonary alveolar proteinosis (PAP) is a rare syndrome characterized by surfactant accumulation in the lungs and alveolar macrophage dysfunction.
• This condition leads to progressive dyspnea, hypoxemic respiratory failure, secondary infections, and pulmonary fibrosis.
• PAP pathogenesis is often driven by impaired cholesterol clearance in macrophages, hindering surfactant clearance.

Purpose of the Study:

• To provide a comprehensive overview of Pulmonary Alveolar Proteinosis (PAP).
• To detail the classification, pathogenesis, prevalence, and management of PAP.
• To highlight emerging therapies targeting PAP's underlying mechanisms.

Main Methods:

• Review of existing literature on Pulmonary Alveolar Proteinosis.
• Classification of PAP based on pathogenetic mechanisms: primary (autoimmune, hereditary), secondary, and congenital.
• Analysis of prevalence data and current management strategies, including whole-lung lavage.

Main Results:

• PAP is classified into primary (autoimmune or hereditary), secondary, and congenital forms.
• Autoimmune PAP, resulting from GM-CSF autoantibodies, accounts for over 90% of cases.
• Prevalence is at least 7 cases per million, affecting all demographics, with higher prevalence in smokers.

Conclusions:

• Understanding PAP's diverse etiologies, particularly the role of GM-CSF signaling, is crucial.
• Current management focuses on symptom improvement, with whole-lung lavage as an effective surfactant removal method.
• Novel therapies targeting GM-CSF signaling, immune modulation, and cholesterol homeostasis are under development for PAP.