Table of ContentsView AllTable of ContentsSynthesisStructureIgE Receptors and Their FunctionAssociated Health ConditionsIgE Allergy TestAnti-IgE Medications
Table of ContentsView All
View All
Table of Contents
Synthesis
Structure
IgE Receptors and Their Function
Associated Health Conditions
IgE Allergy Test
Anti-IgE Medications
Increased blood levels of IgE are associated withallergies(includingatopic dermatitis), parasitic and certain viral infections, some types of immunodeficiency, inflammation,asthma, and some cancers, includingHodgkin’s and non-Hodgkin’s lymphoma. Blood tests for IgE can be used to diagnose allergies.
This article will include a simple overview of the structural makeup and production of IgE, the function of IgE, its significance in certain conditions/diseases, the role of serum IgE testing, and medications that affect IgE.
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What Causes Allergies? Common Allergens and Other Factors
In the case ofallergens, the substance typically is not harmful to most people. However, people who generate IgE to allergens can be negatively affected once they develop a sensitization. This process takes place in lymphoid tissues such as the tonsils, adenoids, and bone marrow.
IgE then diffuses through the tissues and into the bloodstream. Local synthesis (production) of IgE can occur in the bronchial and nasal mucosa.
IgE is a Y-shaped protein, made of two light chains and two heavy chains of peptides (building blocks of protein). The heavy chains form the body and arms of the Y shape, and the light chains attach just to the arms of the Y shape.
A defining characteristic of IgE is the heavy chains, called epsilon. IgE has four constant regions, which makes the molecule heavier. Both the light chains and the heavy chains have a variable region at the end of the Y arms, which binds to specific antigens.
IgE binds to two types of receptors—high-affinity receptors and low-affinity receptors.
High-Affinity Receptors
High-affinity receptors (where IgE binds more tightly) are located mostly on basophils and mast cells. These are immune system blood cells with granules containing chemicals involved in allergic reactions.
IgE binds to these cells in the presence of specific antigens (substances such asallergensthat provoke an immune response). The binding sets off a chain reaction that causes the cells to release chemical immune mediators (such ashistamine), which are responsible for the symptoms of an allergic reaction.
Low-Affinity Receptors
Low-affinity receptors (where IgE binds less avidly) are located on several types of cells, including B cells, T cells, dendritic cells, monocytes, macrophages, neutrophils, eosinophils, and platelets.
IgE binding triggers different effects in cells. For example, when IgE binds to a specific marker on B cells, it inhibits (stops the growth of) the synthesis of more IgE. This is called negative feedback and is how the immune system regulates itself.
IgE is associated with these conditions:
Serum IgE testing may be used to diagnose allergies. The total amount of IgE in your blood can be measured. Another type of test, called a specific IgE test, can also be used. A specific IgE test measures how much IgE your body makes to a specific allergen.
However, specific IgE tests may have false positives, showing you are allergic to an allergen when you are not.For example, you don’t have any allergic symptoms when you eat peanuts, but the test shows an elevation in peanut-specific IgE. This is called sensitization and healthcare providers use this test result to confirm what the patient has reported in their clinical history.
Othertypes of allergy testsmay be used, such as skin tests. Serum IgE may also be used to screen for parasitic infections or aid in diagnosing other illnesses.
Other medications that may be used to treat IgE-associated conditions, such as steroids, target the immune response more broadly and are not as specific to IgE.
Summary
Immunoglobulin E (IgE) is a complex antibody with several functions but is best known for its role in the allergic response. It is an important antibody in fighting off parasites. Extremely high or undetectable levels of IgE are linked to various health problems.
While research continues, a better understanding of the function of IgE has led to the development of important medications that can improve the lives of individuals with IgE-associated illnesses.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
UpToDate.The biology of IgE.
Asthma and Allergy Foundation of America.Allergens and allergic asthma.
Immune Deficiency Foundation.Hyper IgE syndrome.
McCraw AJ, Chauhan J, Bax HJ, et al.Insights from IgE immune surveillance in allergy and cancer for anti-tumour IgE treatments.Cancers. 2021;13(17):4460. doi:10.3390/cancers13174460
MedlinePlus.Allergy blood test.
Xolair (omalizumab).Prescribing information.
Food and Drug Administration.Xolair label.
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