Alpha-1 antitrypsin (AAT) is a protein produced by the liver that circulates throughout the bloodstream, reaching various tissues, particularly the lungs. It plays a protective role in the body. Measuring AAT levels provides valuable insights into an individual’s health status, helping identify potential health concerns and guide medical care.
Alpha-1 Antitrypsin’s Role
Alpha-1 antitrypsin primarily functions as a protease inhibitor, a protein that neutralizes destructive enzymes. Synthesized predominantly in the liver, it is released into the bloodstream and diffuses into tissues. Its main activity involves safeguarding delicate tissues, especially in the lungs, from damage caused by neutrophil elastase. Neutrophil elastase, an enzyme released by immune cells during inflammation and infection, helps break down harmful substances. However, without sufficient AAT, this enzyme can inadvertently attack and degrade healthy lung tissue.
The Alpha-1 Antitrypsin Test
An alpha-1 antitrypsin test determines if a person has sufficient levels of this protective protein. Healthcare providers often recommend this test for individuals with unexplained lung conditions like emphysema or chronic obstructive pulmonary disease (COPD). It is also indicated for people with liver disease, especially if it appears in childhood, as AAT deficiency can impact liver health. A family history of AAT deficiency or related lung and liver conditions also prompts testing. The testing process is straightforward, typically involving a simple blood draw from a vein in the arm, though a cheek swab may also be used for genetic analysis.
Interpreting Alpha-1 Antitrypsin Test Results
Interpreting alpha-1 antitrypsin test results involves comparing measured AAT levels to a normal range. This normal range can vary slightly between different laboratories due to testing methods. Low AAT levels suggest alpha-1 antitrypsin deficiency, meaning the body lacks enough protective protein. Such a deficiency significantly increases the risk of developing lung conditions like emphysema or liver diseases such as cirrhosis.
Conversely, elevated AAT levels indicate an acute phase reaction. This means the body is responding to inflammation, infection, or stress. Pregnancy and oral contraceptives can also lead to higher AAT levels. While generally a protective response, high levels are less concerning than low levels for this test. A healthcare professional must interpret all test results, considering them alongside a patient’s medical history and other clinical findings for an accurate diagnosis.
Alpha-1 Antitrypsin Deficiency and Its Management
Alpha-1 antitrypsin deficiency (AATD) is a genetic condition caused by mutations in the SERPINA1 gene, which instructs the body to produce AAT. Abnormally low or improperly formed AAT leads to health complications, primarily affecting the lungs and liver. In the lungs, insufficient AAT allows neutrophil elastase to damage delicate air sacs, leading to emphysema and bronchiectasis. The liver can also be affected, as abnormal AAT proteins can accumulate there, potentially causing scarring (cirrhosis) and, rarely, liver cancer.
Management of AATD aims to mitigate symptoms and slow disease progression. Augmentation therapy, a specific treatment for lung-related AATD, involves regular intravenous infusions of AAT protein from healthy human plasma. This therapy increases protective AAT levels in the lungs, preventing further damage.
Lifestyle adjustments are crucial, including avoiding smoking and minimizing exposure to environmental irritants like dust and pollution. Medical monitoring involves regular check-ups, symptom management with medications like bronchodilators and corticosteroids, and, if needed, oxygen therapy or pulmonary rehabilitation. Vaccinations against hepatitis A and B, influenza, and pneumococcal infections are recommended to reduce complication risks. In severe cases of lung or liver damage, transplantation may be considered.