Immunoglobulin D (IgD)

What sample is needed for Immunoglobulin D (IgD)?

1. The best sample is fresh serum.
2. The sample can be stored at 4 °C for less than 72 hours.
3. Avoid lipemic or hemolyzed samples.
4. Stable for 6 months at -20 °C.

What are the indications for  Immunoglobulin D (IgD)?

• It may be advised in IgD myelomas.

How will you discuss the pathophysiology of Immunoglobulin D (IgD)?

1. IgD is a monomer with a molecular weight of 180,000 and is 7 S.
2. It is 0.2% of the total immunoglobulins and approximately  3 to 5 mg/dl.
   1. It exists in very low concentrations in the plasma.
   2. It has two kappas (κ) or lambda (λ) chains.
   3. Two deltas (δ) heavy chains.
3. It is 1% of the plasma membrane of the mature B-lymphocytes.
   1. IgD is a cell membrane associated with IgM on the surface of B-lymphocytes.

4. There are isolated reports that it has activity against insulin, penicillin, milk, diphtheria toxoid, nuclear antigen, and thyroid antigen.
5. Its half-life is 2 to 3 days.
6. It can not cross the placental barrier.
7. IgD can bind to rubella, diphtheria, measles, and Streptococcus.
8. This is very sensitive to proteolysis.

9.  IgD’s main function is unknown but may be involved in differentiating B-lymphocytes.

What are the functions of immunoglobulin D (IgD)?

1. IgD, one of its functions, signals the B-lymphocytes.
2. Secreted IgD enhances mucosal homeostasis and immune surveillance.
3. IgD armed the myeloid effector cells like basophils and mast cells.

What is the normal level of Immunoglobulin D (IgD)?

Source 1

• Cord blood = >2 mg/dL
• >16 years = <15 mg/dL
• Newborn = <1.0 mg/dL
• Adult = <8 mg/dL
  • To convert to SI unit x 10 = mg/L

Another source

•  0.3 to 3.0 mg/dl
• Newborn  =  <1.0 mg/dL
• Adult        =  <8 mg/dL

What are the causes of raised levels of Immunoglobulin D (IgD)?

1. In patients with multiple Myeloma cases (IgD myeloma)
2. It may be seen in hyperimmunoglobulinemia IgD syndrome.
3. Autoimmune disease.
4. Chronic infections.

What are the causes of decreased levels of immunoglobulin D (IgD)?

1. Hereditary deficiencies.
2. Non-IgD-myeloma.
3. Infancy early childhood.
4. Acquired immune deficiency (AIDS).

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