What is IgG IgA IgM IgE IgD?

Understanding Immunoglobulins: IgG, IgA, IgM, IgE, and IgD
Immunoglobulins, commonly known as antibodies, are crucial components of the immune system, playing a vital role in defending the body against pathogens such as bacteria and viruses. There are five primary classes of immunoglobulins: IgG, IgA, IgM, IgE, and IgD, each serving distinct functions in immune response.
IgG: The Most Abundant Antibody
IgG is the most prevalent antibody in the bloodstream, accounting for about 75-80% of the total immunoglobulin pool. It is primarily responsible for long-term immunity and is the only antibody that can cross the placenta, providing passive immunity to the fetus. IgG is essential for neutralizing toxins and viruses, opsonizing pathogens for phagocytosis, and activating the complement system, which enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism.
IgA: The Mucosal Protector
IgA is predominantly found in mucosal areas, such as the gut, respiratory tract, and urogenital tract, as well as in secretions like saliva, tears, and breast milk. It plays a critical role in mucosal immunity by preventing the colonization of pathogens on mucosal surfaces. In infants, IgA from breast milk is particularly important for protecting against infections.
IgM: The First Responder
IgM is the first antibody produced in response to an infection. It is primarily found in the blood and lymphatic fluid and is effective in forming complexes with antigens, which helps in their elimination. IgM is also a potent activator of the complement system, making it crucial in the early stages of immune response.
IgE: The Allergy Mediator
IgE is associated with allergic reactions and responses to parasitic infections. It binds to allergens and triggers histamine release from mast cells and basophils, leading to symptoms of allergies such as itching, swelling, and respiratory issues. Elevated levels of IgE are often found in individuals with allergies or asthma.
IgD: The Unknown Function
IgD is the least understood of the immunoglobulins. It is primarily found on the surface of immature B cells and plays a role in the initiation of B cell activation. While its exact function in the immune response remains unclear, it is believed to be involved in the regulation of B cell maturation and activation.
Conclusion
In summary, the five classes of immunoglobulins—IgG, IgA, IgM, IgE, and IgD—each play unique and essential roles in the immune system. From providing long-term immunity to mediating allergic responses, these antibodies are fundamental to maintaining health and combating infections. Understanding their functions not only aids in comprehending the immune system but also highlights the complexity of our body’s defense mechanisms.

Why would a doctor order an immunoglobulin test?

Why Are Immunoglobulin Tests Done? Doctors may check immunoglobulin levels to see if a person has an infection or is protected from getting an infection (is immune to it). Doctors also use immunoglobulin tests to help diagnose immunodeficiencies (when the immune system isn’t working as it should).

What does IgG, IgA, and IgM test for?

An immunoglobulins blood test measures the amounts of IgM, IgG, and IgA in your blood to help diagnose different types of health conditions that may affect your immune system.

What autoimmune disease causes high immunoglobulin?

High values
Levels of IgA also get higher in some autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus (SLE), and in liver diseases, such as cirrhosis and long-term (chronic) hepatitis. IgG. High levels of IgG may mean a long-term (chronic) infection, such as HIV, is present.

What is the difference between IgE and IgA and IgM?

IgM is mostly found in your blood. IgA is found at high levels in fluid your mucus membranes make, such as saliva, tears, and nasal secretions. IgE is mostly attached to immune system cells in your blood.

What are the 5 types of immunoglobulins and what are their functions?

There are 5 types of heavy chain constant regions in antibodies (immunoglobulin) and according to these types, they are classified into IgG, IgM, IgA, IgD, and IgE. They are distributed and function differently in the body.

What level of IgA is concerning?

High IgA (>4g/L)
Elevated IgA levels are nonspecific, but can be seen in pulmonary and gastrointestinal inflammatory diseases, some autoimmune conditions, liver disease, and plasma cell disorders.

What does it mean when your IgG is positive?

High levels of IgG may mean you have an infection or an inflammatory or autoimmune disease that involves your central nervous system. An autoimmune disorder causes your immune system to attack your own healthy cells by mistake, which can lead to serious health problems.

What cancers cause high IgG levels?

Accumulating evidence shows that immunoglobulins (Igs), especially IgG, are highly expressed in a variety of non-B cells from a variety of tumor tissues, including breast carcinoma (6), esophagus carcinoma (7), lung cancer (8,9), prostate cancer (10), bladder cancer (11), papillary thyroid cancer (12) and colorectal …

What does IgA do for the body?

Immunoglobulin A (IgA) is an antibody blood protein that’s part of your immune system. Your body makes IgA and other types of antibodies to help fight off sickness.

What autoimmune diseases cause high IgG levels?

Individuals with systemic lupus erythematosus and rheumatoid arthritis are characterized by the presence of high levels of circulating IgM and IgG autoantibodies.