Rare Classroom: Autoimmune Pulmonary Alveolar Proteinosis

Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Autoimmune Pulmonary Alveolar Proteinosis

Sometimes just called alveolar proteinosis.

What is Autoimmune Pulmonary Alveolar Proteinosis?

  • Autoimmune pulmonary alveolar proteinosis is a rare lung disorder
  • This disorder causes the abnormal buildup of surfactant-based lipoprotein compounds with the lung’s alveoli, or air sacs
  • These excess compounds result in problems with lung expansion and gas exchange
  • The disease was first described in 1958 by physicians Averill Liebow, Benjamin Castleman, and Samuel Rosen

How Do You Get It?

  • Pulmonary alveolar proteinosis has a number of causes, but the most common form is the autoimmune form
    • This is a ‘primary’ form of the disease, meaning that there is no known external condition leading to the development of the disease
    • This autoimmunity is typically targeting granulocyte-macrophage colony stimulating factor (GM-CSF)
    • This factor is vital to the normal development of alveolar macrophages
  • The lack of macrophage function and activity results in the accumulation of surfactant compounds
  • Risk factors for autoimmune pulmonary alveolar proteinosis include being male and smoking tobacco

What Are the Symptoms?

  • Symptoms of autoimmune pulmonary alveolar proteinosis include:
    • Coughing
    • Shortness of breath
    • Weight loss
    • Fever
    • Vulnerability to infections of the lungs
  • The clinical course of the disease is inconsistent. Some patients have mild, stable symptoms, whereas other may see steady progression that can be fatal
  • Others may see spontaneous remission

How Is It Treated?

  • The primary treatment for autoimmune pulmonary alveolar proteinosis is whole lung lavage.
    • This procedure is conducted under anesthesia and involves one lung being pumped with oxygen while the other is filled with warm saline solution and then drained
    • When the lung is drained, the built-up compounds are removed along with the solution
    • In many cases, patients see long-term improvement after this procedure
  • Other therapies being evaluated include inhaled/subcutaneous GM-CSF and rituximab, a monoclonal antibody widely used for the treatment of other autoimmune disease
  • Lung transplant may be attempted if other treatments are unsuccessful

Where Can I Learn More???

  • Check out our cornerstone on this disease here.
  • Learn more about this disease from the PAP Foundation.

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