Serum Alpha-1 Antitrypsin (AAT) determinations are obtained in individuals with a family history of emphysema, because there is a familial tendency for Alpha-1 Antitrypsin Deficiency. Deficient or absent serum levels of Alpha-1 Antitrypsin can cause the early onset of disabling Emphysema. A similar deficiency in AAT is seen in children with Cirrhosis and other liver diseases.
Alpha-1 Antitrypsin is also an acute-phase reactant protein that is elevated in the presence of inflammation, infection, or malignancy. It is not specific regarding the source of the inflammatory process.
Alpha-1 Antitrypsin blocks releasing Endoproteases. Endoproteases are protein catabolic enzymes secreted in human body by degenerating and dying cells. As in the case of Trypsin and Neutrophil Elastase, activation of Endoproteases breaks down elastic fibers and Collagen, especially in the lung.
Alpha-1 Antitrypsin Deficiencies can be a result of genetic causes. or acquired. If Alpha-1 Antitrypsin test indicates the possibility of Alpha-1 Antitrypsin Deficiencies, genetic counseling is indicated. Other family members should be tested to determine their and their children’s risks.
Alpha-1 Antitrypsin Deficiencies can also be acquired. Aquired Alpha-1 Antitrypsin Deficiencies can be seen in patients with Protein-deficiency Syndromes and are usually accompanied with deficiencies of other proteins. People with AAT deficiency develop severe panacinar (although usually more severe in the lower third of the lungs) emphysema in the third or fourth decade of life.
Symptoms of Alpha-1 Antitrypsin Deficiencies include progressive dyspnea with minimal coughing. Chronic bronchitis is prominent in those patients with deficient AAT levels who smoke. Bronchiectasis can also occur in these patients.
Inherited AAT deficiency is associated with symptoms earlier in life than acquired AAT disease. Inherited AAT is also commonly associated with liver and biliary disease. AAT Genetic Phenotyping (AAT phenotyping) has shown that most persons have two AAT “M” genes (designated as MM) and AAT levels over 250 mg/dL. “Z” and “S” gene mutations are typically associated with alterations in serum levels of AAT. Individuals who are ZZ or SS homozygous have serum levels below 50 mg/dL and often near zero.
Individuals who are MZ or MS heterozygous have diminished or low-normal serum levels of AAT. Approximately 5% to 14% of the adult population have this heterozygous state, which is considered to be a risk factor for emphysema. Homozygous individuals have severe pulmonary and liver disease very early in life. AAT Phenotyping is particularly helpful when blood AAT levels are suggestive but not definitive.
AAT is qualitatively measured using immunochemical methods. Quantification is possible but rarely useful with phenotyping. Routine serum protein electrophoresis is a good screening test for AAT deficiency, because AAT accounts for about 90% of the protein in the alpha1-globulin region on electrophoresis.
Normal Alph-1 Antitrypsin Levels
Serum Normal Alpha-1 Antitrypsin Levels range between 85 and 213 mg/dL (or .85 to 2.13 g/L using SI units).
Causes of Alph-1 Antitrypsin Levels False Indications
- Serum levels of Alpha-1 Antitrypsin can double during pregnancy.
- Drugs that may cause increased Alpha-1 Antitrypsin levels include Oral Contraceptives.
Causes of High Alph-1 Antitrypsin Levels
Because AAT is an acute-phase reactant protein, High Alph-1 Antitrypsin Levels can be expected when the body is subjected to any inflammatory reaction or stress. High Alph-1 Antitrypsin Levels are associated with:
- Acute Inflammatory Disorders.
- Chronic Inflammatory Disorders.
- Thyroid Infections.
Causes of High Alph-1 Antitrypsin Levels
The following diseases are a result of Endoproteases working uninhibited (no AAT available) within the body. Collagen is broken down, setting up the destruction of lung and liver structures:
- Early Onset of Emphysema (adults).
- Neonatal Respiratory Distress Syndrome.
- Cirrhosis (children).
Low Serum Proteins: Diseases such as Malnutrition, End-stage Cancer, Nephrotic Syndrome, Protein-losing Enteropathy, and Hepatic Failure are associated with lack of protein synthesis. AAT is a protein and therefore will not be produced in adequate quantities in these diseases.