Immunoglobulin Electrophoresis (Ig)

Also known as: Ig; Antibody; Immune serum globulin; Immune globulin; Gamma globulin

1) Special proteins produced by the body in response to foreign substances including bacteria and viruses; there are five structurally distinct classes of immunoglobulins produced by plasma cells in the bone marrow and other lymphoid tissue that bind to and neutralize foreign substances (antigens). The five major kinds of immunoglobulins are A, D, E, G and M.

2) A solution made from human blood plasma that contains concentrated antibodies that protect against specific diseases, such as short-term protection against certain infections and Rh sensitization during pregnancy; it is made from human blood plasma that has been pooled, processed from donated blood, and purified.

Sample

• Venous blood is needed to prepare the serum.

Purpose of the test

• It is advised to diagnose many diseases like Multiple Myeloma etc.
• If there is a spike in gamma band in serum electrophoresis, then Ig electrophoresis is advised.
• This test is advised in:
  • Hypersensitivity reactions.
  • Immune deficiency.
  • Autoimmune diseases.
  • Chronic infections.
  • Intrauterine fetal infection.

Serum proteins consist of:

1. Albumin
2. Globulins.

IgG

1. can cross the placental barrier, So it can enter the fetal circulation.
2. IgG concentration:
   1. Serum = 17 to 29 mg/mL.
   2. Milk = 1 to 3 mg/mL.
   3. Colostrum = 30 to 70 mg/mL.
3. IgG protect the newborn for the first few months of life.
4. IgG is effective in infection in the secondary response.
5. Major function is neutralization of toxins and destruction of the infectious agents.
6. It can help in phagocytosis and activates the complement system.
7. IgG has 4 subclasses as IgG1, IgG2, IgG3, and IgG4.
8. IgG moves in the beta region and some in gamma zone of electrophoresis.
9. IgG1 cross the placental barrier and protect the neonates for the first three months of postnatal life.
10. IgG1 and IgG3 bind with Fc receptor of phagocytic cells.
11. IgG1, IgG2, and IgG4 have a half-life of 22 days.
12. IgG3 has a half-life of 7 days. 

IgA

1. It is present in the secretions like saliva, GI tract, respiratory system, and tears.
2. IgA is present in small amount in the blood.
3. 10 to 15 % of the Ig is IgA.
4. IgA exists as a monomer form and dimer form.
5. IgA migrates in the beta-gamma region.
6. IgA one form is called as secretory IgA found in tears, saliva, sweat, milk and colostrum, GI tract and bronchi.
7. IgA is mainly formed by the plasma cells of GI tract, bronchi. and breast ductules of lactating mother.
8. IgA activates complement by alternative path.
9. IgA concentration:
   1. Serum =  0.5 to 5 mg/mL.
   2. Milk = 3 to 7 mg/mL.
   3. Colostrum = 9.5 to 10 mg/mL.

IgM

1. IgM is blood ABO grouping protein.
2. This is effective against bacterial infection as a primary response.
3. IgM can not cross the placental circulation, so its presence in the newborn baby indicates intrauterine infections like Rubella, CMV, or sexually transmitted disease(STD).
4. IgM is third most Ig 5 to 10 % of the total Ig.
5. IgM concentration:
   1. Serum = 1 to  5 mg/mL.
   2. Milk = 0.3  to 0.9 mg/mL.
   3. Colostrums = 2.5 – 3.2 mg/mL.
6. IgM exists in two forms:
7. IgM monomer acts as a membrane receptor.
8. IgM pentamer acts as an antibody. it consists of 5 basic units of immunoglobulin.
9. IgM because of its large size cannot enter the extravascular space.
10. B – lymphocytes have a receptor for IgM.
11. IgM appears first in the encounter of antigen as a primary immune response.
12. The naturally occurring anti-A and anti-B are IgM type.
13. IgM can activate the complement system and also cause agglutination.
14. IgM present in the cord blood and neonates >25 mg/dL is diagnostic of intrauterine infection.

IgE

1. IgE is raised mainly in the allergic reaction and this is also called as Reagin.
2. IgE once produced is strongly bound to mast cell and basophils, so very small amount found in the serum.
3. IgE two molecule crosslink on the surface of mast cells or basophils and stimulate the production of histamine or histamine-like substances.
4. IgE gives rise to asthma, hay fever, urticaria, and eczema.

IgD

1. IgD function is not clear but considering that it is needed for the activation of immune cells.
2. IgD is 1 % of the total Ig.
3. IgD acts as a surface receptor for antigen on B lymphocytes.
4. IgD primary function is still unknown.
5. IgD is in a very small amount in the circulation.

Table showing Immunoglobulins in various ages:

Age	IgG	IgM	IgA	IgD	IgE
Adult	565 to 1765 mg/dL	55 to 375 mg/dL	85 to 385 mg/dL	minimum	minimum
2 to 5 months	200 to 700 mg/dL	25 to 100 mg/dL	4 to 80 mg/dL
One year	430 to 1200 mg/dL	35 to 125 mg/dL	15 to 110 mg/dL
4 to 12 years	460 to 1600 mg/dL	50 to 250 mg/dL	25 to 350 mg/dL

Increased IgG level is seen in:

1. Multiple myelomas (Monoclonal IgG gammopathy).
2. Hyperimmunization reaction.
3. Chronic granulomatous infection.
4. Chronic liver diseases.
5. Autoimmune diseases like rheumatoid arthritis, Sjogren’s syndrome, and SLE.

Decreased IgG level is seen in:

1. Agammaglobulinemia.
2. Wiskott-Aldrich syndrome.
3. AIDS (acquired immune deficiency syndrome).
4. Nephrotic syndrome.
5. Protein-losing enteropathy.

Increased IgM level is seen in:

1. Waldenstrom macroglobulinemia.
2. Chronic infections.
3. Autoimmune diseases like rheumatoid arthritis , and SLE .
4. Acute infection as primary immune response.
5. Chronic liver diseases like biliary cirrhosis.

Decreased IgM level is seen in:

1. Agammaglobulinemia.
2. Hypoproteinemia is seen in nephrotic syndrome and protein-losing enteropathy.
3. AIDS
4. Immunosuppression due to drugs like steroids and dextran.

Increased level of IgA seen in:

1. Primary biliary cirrhosis.
2. Inflammatory bowel disease.
3. Chronic infectious.

Decreased level of IgA seen in:

1. Hypoproteinemia due to nephrotic syndrome and protein-losing enteropathy.
2. Ataxia.
3. Immunosuppression due to drugs like steroids.
4. Congenital isolated deficiency of IgA.
5. Telangiectasia.

Increased IgE level is seen in:

1. Allergic reactions like hay fever, asthma, eczema, and parasites.
2. In anaphylactic reaction.

Decreased IgE level seen in:

1. Agammaglobulinemia.

Increased monoclonal gammopathy is seen in:

1. Multiple myelomas.
2. Waldenstrom macroglobulinemia.

Increased polyclonal gammopathy is seen in:

1. Amyloidosis.
2. Chronic liver disease.
3. Chronic infections.
4. Autoimmune diseases.

Increased monoclonal gammopathy is  seen in Urine:

1. Waldenstrom macroglobulinemia.
2. Multiple myelomas.

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Possible References Used

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