Immunoglobulin E (IgE)
- The best sample is fresh serum.
- Used to detect allergic diseases.
- Advised when the patient have:
- Itching of the skin, and itching of the eyes.
- Urticaria and hives.
- Asthma and difficulty in breathing.
- Skin diseases like eczema.
- A cough, congestion.
- Persistent diarrhea, nausea, and vomiting.
- IgE exists as a monomer form with a molecular weight of 190,000 and is 7S.
- It has an extra domain in the constant portion.
- It has:
- Two epsilon (ε) heavy chains.
- One pair of kappa (κ) or lambda (λ) chains.
- It’s Fc region binds strongly to the receptors on the mast cells and basophil along with antigens.
- It is 0.004 % of the total immunoglobulins.
- Its half-life is 2 days.
- It is mainly involved in type 1 hypersensitivity reaction.
- It cannot activate the complement system via the classical pathway.
- It is present in the serum of a healthy person is extremely low concentration.
- It attaches to the receptors on basophils and mast cells.
- There are low-affinity receptors present on the surface of B-lymphocytes and eosinophils.
- It can not cross the placental barrier.
|Cord blood||At term ∼1% of the maternal value|
|0 to 4 days||<1.5|
|5 days to 12 month||<15|
|1 to 5 year||<60|
|6 to 9 year||<90|
|10 to 16 year||<200|
|Adult||3 to 423|
- To convert into SI unit x 1.0 = kIU/L
- 150 ng/ml on the topic (non-allergic) person.
- or .002 to 0.2 mg/dl
- Values vary because of the methodology used.
The raised level is seen in:
- Allergic diseases like asthma, skin diseases.
- Parasitic infestation
- Multiple myeloma producing monoclonal IgE.
- Hyper IgE syndrome.
The decreased level is seen in: