This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare autoimmune lung disorder. It is the most common form (90% of the cases) of pulmonary alveolar proteinosis (PAP). Most cases affect adults between the ages of 20-50 years. Some people may not show symptoms, while others may have progressive difficulty breathing and shortness of breath upon exertion. Other signs and symptoms may include a dry, chronic cough; fatigue; weight loss; chest pain; and a general feeling of ill health. In rare cases, coughing up of blood, rounding and swelling of the tips of the fingers, and cyanosis may be present.[3716] Autoimmune PAP is caused by an immune system malfunction, due to IgG antibodies that block the granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) effect. GM-CSF is a protein that regulates clearance of surfactant (a mix of protein and fat) by alveolar macrophages. The surfactant pile up in the air sacs of the lungs (alveoli), and eventually lead to an inability to breath.[3716][12978] The standard treatment is a procedure called lung lavage. A drug called GM-CSF might effectively treat aPAP.[12978]
Other PAP forms include congenital PAP, a very rare form that occurs in some newborns, caused by disorders of surfactant production; hereditary PAP, where people are born with genetic mutations that destroy the function of the proteins (receptors) on alveolar macrophages that interact with GM-CSF; and, secondary PAP, which occur in people with another disease or dust exposure.[3716][12978]
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