CINCINNATI A tale of two sisters has helped researchers solve a medical mystery and discover a familial genetic mutation that causes an inherited form of the lung disease Pulmonary Alveolar Proteinosis (PAP).
Reporting their results in the Nov. 24 Journal of Experimental Medicine, a research team led by Cincinnati Children's Hospital Medical Center also points to the possibility of an inhaled therapy to overcome a chain of molecular events that lead to PAP. The lungs of people with PAP fill with pulmonary surfactant, a substance composed of lipids (fats) and proteins, causing labored breathing and respiratory failure. Surfactant's normal role is to coat lung tissues and keep the lungs from collapsing
Finding an effective, non-invasive therapy would dramatically improve quality of life for children and adults with PAP, said Bruce Trapnell, M.D., a physician/researcher in the division of Pulmonary Biology at Cincinnati Children's and the report's senior author.
"This is the first data to demonstrate familial PAP in humans and the critical role of the gene CSF2RA to balanced surfactant levels in the lung," Dr. Trapnell said. "These findings provide a basis for developing better forms of treatment that would be a major benefit to patients."
The current front-line treatment is whole-lung wash, where a tube is inserted into the airway under anesthesia to flush out the lungs.
People with PAP can also acquire secondary infections. This happens when immune system cells in called macrophages and neutrophils, which ingest and destroy foreign matter, are deprived of the effects of GM-CSF. The lack of GM-CSF activity impairs the cells' ability to remove infectious organisms from the lungs.
The multi-institutional team studied the cases of two sisters, ages 6 and 8, whose PAP progressed slowly prior to diagnosis. For two years prior to diagnosis, the younger sister had suffered from labored breathing and had below
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Cincinnati Children's Hospital Medical Center