What is Autoimmune pulmonary alveolar proteinosis (aPAP)

Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare lung disease that is hard to diagnose and often misdiagnosed. This is because its symptoms are also common to other respiratory illnesses like pneumonia, bronchitis, and asthma. In aPAP, a substance called surfactant builds up in the air sacs of the lungs (alveoli) that leads to problems getting oxygen into the body. Surfactant is a naturally produced fluid that is normally present in the lungs at a certain level, but when surfactant builds up it’s hard to breathe.

In the United States, about 7 in 1 million people are diagnosed with aPAP, which is the most common form of pulmonary alveolar proteinosis (PAP), and it makes up about 90% of PAP cases. However, because many doctors are not familiar with aPAP, they don’t even know to test for it – making the true number of cases unknown. Although symptoms of aPAP can appear as early as childhood, most people are diagnosed in their 30s to 50s. It’s not more common in any sex, race, or region of the world.

In aPAP the immune system mistakenly targets and blocks a special protein, called granulocyte-macrophage colony-stimulating factor (GM-CSF), from activating white blood cells, called macrophages, that are responsible for removing excess surfactant from the air sacs in the lungs. As a result, surfactant builds up, which makes it hard to breathe. This blocking is caused by antibodies produced by the immune system, called GM-CSF autoantibodies.

Some common signs and symptoms of aPAP include shortness of breath, persistent cough, and overwhelming fatigue including difficulty climbing stairs or walking. Because aPAP symptoms mimic more common respiratory conditions, it can take an average of 18 months from the time a person starts to feel symptoms to be diagnosed.

Since many pulmonologists are not familiar with testing for aPAP specifically, they may suggest invasive tests that may require hospitalization such as bronchoscopy or a lung biopsy. However, a simple, accurate, and non-invasive blood test – aPAP ClearPath^TM – designed to detect the autoantibodies that cause aPAP can help confirm or rule out a diagnosis at no cost to you or your doctor. Your pulmonologist can get information and order the aPAP ClearPath^TM blood test by visiting www.aPAPclearpath.com.