General Information about Rare Lung Disease
Rare lung diseases, defined as a disease that affects less than 200,000 individuals, impacts individuals across a wide swath of society. Rare lung diseases include a wide spectrum of disorders, including alpha-1 antitrypsin deficiency (AATD), lymphangioleimyomatosis (LAM), Tuberous sclerosis, pulmonary alveolar proteinosis (PAP) and hereditary interstitial lung diseases. Many of the rare lung diseases have provided unique opportunities to investigate mechanisms shared by more common lung diseases. For example, alpha 1 antitrypsin (AAT) deficiency is a rare disorder that causes pulmonary emphysema. Investigations into the disease showed that mutations in the gene for AAT protein were responsible for the destructive lung disease. This led to the discovery that AAT is a protein that inhibits elastases, enzymes which attack structural components of the lung, and launched an entire field of investigations into the role of these enzymes in the development of emphysema, even in patients who do not have genetic deficiency of AAT and offer hope for future therapies to harness this destructive process.
Another example of the impact of basic science research is our understanding of the pulmonary alveolar proteinosis, an uncommon lung disease where abnormal protein builds up in the alveoli and impairs normal gas exchange. Until recently, the only treatment option was to perform whole lung lavage-a procedure requiring general anesthesia, in which the lung is washed out with over 20 liters of fluid. Patients required repeated lavages every 3-12 months because of disease relapse. Recently, scientists developed a mouse model in which the gene encoding for the GM-CSF (granulocyte-monocyte colony stimulating factor) protein was inactivated or ‘knocked out.’ Surprisingly these mice developed a lung disease that resembled pulmonary alveolar proteinosis. When investigators then measured the levels of GM-CSF in pulmonary alveolar proteinosis patients, the GM-CSF levels were found to be very low and the patients had antibodies to GM-CSF in their blood. Thus, pulmonary alveolar proteinosis now is considered an autoimmune disease. This unexpected discovery has led to improved and easier treatment by replacing the GM-CSF.
These success stories were only possible because of the support of the community for research and education. Because many of these diseases are poorly understand, it is imperative that we continue to support research and education for this diseases, and increase federal support. Our ultimate goal is to improve medical care for patients afflicted with these diseases, and apply the lessons learned to patients afflicted with more common diseases.Source: Lynn Schnapp, MD, Chair, ATS RCMB Assembly