What is the pathophysiology of pulmonary alveolar proteinosis (PAP)?

Updated: Dec 18, 2019
  • Author: Rodolfo Laucirica, MD; Chief Editor: Philip T Cagle, MD  more...
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Animal and human studies indicate that more than one pathway exists for the different forms of pulmonary alveolar proteinosis (PAP). The congenital form of PAP results from multiple genetic abnormalities. These include defects in genes encoding for surfactan protein B or C, transporter molecules within type II pneumocytes, and the beta chain receptor of granulocyte-macrophage colony-stimulating factor (GM-CSF). [2, 3, 4, 5]

Autoimmune PAP is characterized by the presence of anti-GM-CSF antibodies. This leads to a deficiency or malfunction of GM-CSF, which is an integral component of surfactant homeostasis. [6, 7, 8, 9, 10, 11] Analysis of bronchoalveolar lavage (BAL) fluid suggests that the pathogenesis of autoimmune PAP may also involve abnormal clearance rather than excessive production of pulmonary surfactant. [12, 13]

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