Acute Phase Protein – Part 1 – Alpha-1-Antitrypsin (α1-antitrypsin)

Acute-phase protein (Acute Phase Reactants)

• Acute-phase protein is raised in inflammatory conditions.
• When there is an increase in a protein called positive acute-phase protein.
  • In the case of a decrease in the acute phase protein, is called negative phase protein.
• The acute phase proteins (positive) are protein whose concentration increases in the plasma and after the disease episode is over then it decreases and may become normal.

Alpha-1–antitrypsin (AAT, α1-antitrypsin)

Sample

• It is done in the serum of the patient (collect 5 to 10 ml of blood).
• Serum electrophoresis may be advised. 

Indications

1. In case of family history of emphysema.
2. Advised in children with cirrhosis.
3. Advised of acute inflammation, infection or malignancy (non-specific test).

Pathophysiology

1. This is a naturally occurring protease inhibitor.
2. This is synthesized and catabolized in the liver.
3. This important inhibitor of neutrophils elastase which is produced in the process of phagocytosis by these cells.
4. This enzyme reacts with elastin in the tracheobronchial tree and vascular endothelium.
   1. This enzyme prevents the loss of elastic tissue function.
   2. Its deficiency leads to premature emphysema.

                        

5. Its concentration is increased much fold in acute inflammation.

6. Cigarette smoke and volatile irritants lead to the release of proteolytic enzymes from the white blood cells.

7. This is a disease called AAT deficiency, is an inherited condition.
   1. This disease can transfer from parents to children.
8. ATT is a protein which protects the lung. It is formed in the liver.
9. Its deficiency leads to:

1. 1. There is tiredness.
   2. There is weight loss. 
   3. Repeated lung infections.
   4. There is shortness of breath and wheezing.
   5. There may be a vision problem.
   6. There may be tachycardia on standing.
2. This is an increase in acute and chronic inflammation.

Normal

1. 1. Newborn   =  145 to 270 mg/dL.
   2. Adult          =  78 to 200 mg/dL.
   3. Adult > 60 years   =  115 to 200 mg/dL.
   4. Serum electrophoresis showed 90% of ATT in the α1-globulin.
      1. Another source
         1. 85 to 213 mg/dL (0.85 to 2.13 g/L).
      2. Another source
         1. 100 to 200 mg/dL (18.4 to 36.8 µmol/L) by nephelometry.

Test value for the layman:

1. 1. 1. 1. 1. In the case of patients with emphysema.
            2. In children, if they develop cirrhosis or liver diseases.

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