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Sample

Factors influencing the result:

  1. Drugs which will increase the values are: 
    1. Hydralazine.
    2. Phenytoin.
    3. Isoniazid (INH).
    4. Procainamide.
    5. Tetanus toxin and toxoid.
    6. Therapeutic gamma globulins.

Pathophysiology

  1. IgA is the second most common Ig  and it has two subclasses:
    1. IgA 1
    2. IgA2
    3. It is 15%  to 20% of the total Ig.
    4. It has a half-life of 6 days.
    5. It has paired kappa (κ) or lambda (λ) chains,
    6. Two heavy chains.
  2. IgA antibodies are produced by the plasma cells.
  3. The plasma cells are derived from activated B - lymphocytes.
    1. IgA antibodies are found in the digestive system, respiratory system, colostrum, milk, nose, eyes,  and vagina.
      1. IgA is also found in the saliva, tears, and blood.
    2. IgA consists of two monomers joined by J-chain and secretory fragment.
      1. IgA monomer form is found in high concentration in the serum (90 to 450 mg/dL in a normal adult).
  4. The normal structure of IgA

                                          

Functions of IgA

  1. IgA antibody main function is to protect the mucosa which is exposed to various antigens.
  2. It can activate complement by alternative pathways.
  3. It is effective opsonin.
  4. The secretory IgA consists of two 4- chain basic unit (dimeric form), joined by the J-chain.
  5. Deficiency of IgA leads to infection of the gastrointestinal and respiratory system.
  6. It has antiviral activity.
  7. Its major role is the protection of bacteria, viruses, and protozoal infection by preventing their attachment and colonization to the mucosa.

                                 

Normal

Source 1

Age mg/dL
Cord serum 1 to 4
one month 2 to 50
2 to 5 month 4 to 80
6 to 9 month 8 to 80
10 to 12 month 15 to 90
one year 15 to 110
2 to 3 year 18 to 150
4 to 5 year 25 to 160
6 to 8 year 35 to 200
9 to 12 year 45 to 250
>12 year 40 to 350

Source 2

Another source

The increased level is seen in:

  1. Multiple Myeloma
  2. Cirrhosis of liver
  3. Systemic lupus erythematosus
  4. Rheumatoid arthritis
  5. Sarcoidosis
  6. Wiskott-Aldrich syndrome 

The decreased level is seen in:

  1. Hereditary telangiectasia
  2. Type 111 dysgammaglobulinemia
  3. Malabsorption in some cases
  4. Occasional cases of Cirrhosis of liver
  5. Occasional cases of SLE
  6. Occasional cases of Still's disease
  7. Occasional cases of recurrent otitis media
  8. In Agammaglobulinemia
  9. Hereditary thymic aplasia

Possible References Used

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