Alpha-1 antitrypsin is a protein produced in the liver that protects the body’s tissues from being damaged by infection-fighting agents released by its immune system[1]. It is an acute-phase protein and the most abundant serine proteinase inhibitor in human plasma[9]. Its major function is the inhibition of elastase, a substance that can break down tissue, especially in the lung[8]. Alpha-1 antitrypsin is responsible for approximately 90% of the protection against elastolytic activity in the lower airways caused by elastase released from neutrophils[2]. If neutrophil elastases are not opposed, panacinar lung tissue is damaged, and the risk of developing chronic obstructive pulmonary disease (COPD) increases[2].
Alpha-1 antitrypsin deficiency is an inherited condition that can cause lung and liver damage[1]. It is caused by variants in the SERPINA1 gene that provide instructions for making alpha-1 antitrypsin protein[1]. In alpha-1 antitrypsin deficiency, the body’s normal production of alpha-1 antitrypsin is reduced, resulting in the destruction of sensitive lung tissue[1].
Symptoms
The most common symptom of alpha-1 antitrypsin deficiency is shortness of breath after physical activity[8]. Other respiratory symptoms include wheezing, coughing, and recurring respiratory infections[3]. Patients may also experience reduced ability to exercise, fatigue, and rapid heartbeat upon standing[3]. Eventually, patients may develop emphysema, a condition in which the small air sacs in the lungs become damaged[3]. About 10% to 15% of patients with alpha-1 antitrypsin deficiency develop liver disease, with symptoms including a swollen abdomen, swollen feet or legs, and yellowing of the skin and whites of the eyes[3].
Diagnosis
Alpha-1 antitrypsin deficiency may be difficult to diagnose because no single physical sign or symptom can be used to confirm a diagnosis[3]. Genetic testing and blood tests may be used to diagnose the condition[1]. The American Thoracic Society/European Respiratory Society recommends testing high-risk groups, such as all chronic obstructive pulmonary disease patients, all nonresponsive asthmatic adults/adolescents, all cases of cryptogenic cirrhosis/liver disease, subjects with granulomatosis with polyangitis, bronchiectasis of unknown etiology, panniculitis, and first-degree relatives of patients with alpha-1 antitrypsin deficiency[2].
Treatment
There is no cure for alpha-1 antitrypsin deficiency, but the lung diseases that it causes can be treated[5]. The initial treatment is similar to that of emphysema, a type of chronic obstructive pulmonary disease (COPD) [5]. The treatment includes bronchodilators, which make breathing easier by relaxing the muscles around the airways[5]. Bronchodilators can be short-acting or long-acting, and they can be used as needed or every day[5]. Patients may also receive inhaled steroids to reduce inflammation in the airways[5]. In addition, patients should quit smoking and avoid secondhand smoke, protect themselves from environmental dusts or workplace exposure to toxic substances, and get regular exercise and control their weight[10].
The only specific therapy for alpha-1 antitrypsin deficiency is augmentation therapy[5]. During this therapy, preparations of alpha-1 antitrypsin protein that have been isolated from pooled blood of healthy donors are given by weekly intravenous infusion[5]. This elevates the blood levels of alpha-1 antitrypsin to levels that are protective for the lung[5]. Well-designed studies have shown that augmentation therapy helps to preserve lung function and decreases the number and severity of lung infections[5].
In summary, alpha-1 antitrypsin is a protein produced in the liver that protects the body’s tissues from being damaged by infection-fighting agents released by its immune system. Alpha-1 antitrypsin deficiency is an inherited condition that can cause lung and liver damage. Diagnosis may involve genetic testing and blood tests, and treatment may include bronchodilators, inhaled steroids, and augmentation therapy. Patients should also quit smoking, avoid secondhand smoke, protect themselves from environmental dusts or workplace exposure to toxic substances, and get regular exercise and control their weight.
Citations:
[1] https://www.lung.org/lung-health-diseases/lung-disease-lookup/alpha-1-antitrypsin-deficiency/learn-about-alpha-1-antitrypsin-defiency
[2] https://www.ncbi.nlm.nih.gov/books/NBK482180/
[3] https://my.clevelandclinic.org/health/diseases/21175-alpha-1-antitrypsin-deficiency
[4] https://www.atsjournals.org/doi/full/10.1513/AnnalsATS.201507-468KV
[5] https://emedicine.medscape.com/article/295686-overview
[6] https://medlineplus.gov/genetics/condition/alpha-1-antitrypsin-deficiency/
[7] https://medlineplus.gov/ency/article/000120.htm
[8] https://www.sciencedirect.com/topics/medicine-and-dentistry/alpha-1-antitrypsin
[9] https://www.frontiersin.org/articles/10.3389/fphar.2018.00341/full