Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare autoimmune lung disorder. It is the most common form of pulmonary alveolar proteinosis.
Etiology
aPAP 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 piles up in the air sacs of the lungs, and eventually leads to an inability to breathe.
Signs and Symptoms
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:
- Dry, chronic cough
- Fatigue
- Weight loss
- Chest pain
- 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.
Diagnosis
aPAP is diagnosed through pulmonary function tests, radiological examination of the lungs, bronchoscopies, and laboratory tests such as GM-CSF autoantibody and signaling tests.
Management Strategies and Treatment
Therapies for aPAP focus on lung lavage, GM-CSF augmentation, plasmapheresis, and anti-B lymphocyte therapy
For a list of clinical trials relating to aPAP, click here.
Resources
References
McCarthy C, et al. Autoimmune Pulmonary Alveolar Proteinosis. [Updated 2022]. In: American Journal of Respiratory and Critical Care Medicine [Internet]. Available at https://doi.org/10.1164/rccm.202112-2742SO
To learn more about this and other rare lung conditions, visit https://checkrare.com/diseases/lung-diseases/
