Immunoglobulin A (IgA)

Immunoglobulin A (IgA) functions as an antibody and is produced by plasma cells and lymphocytes.Immunoglobulins play a crucial role in the body immune’s system as they attach themselves to foreign substances like bacteria and help in destroying them. Immunoglobulins can reside either on the peripherals of the cells or can circulate freely in the blood. When circulating the immunoglobulins are termed as antibodies.

abbreviated as Ig are of different types called isotypes and there are five Immunoglobulin Isotypes namely IgA, IgD, IgE, IgG, and IgM. These varied types of Immunoglobulins have different biological properties, functional locations and the ability to with different kinds of antigens.

Immunoglobulin A Or Iga

Active: IgA plays a vital role in preventing colonization by pathogens in various mucosal areas such as the gut, saliva, tears, breast milk, respiratory tract, and the urogenital tract. IgA exists in two isotypes, IgA1 and IgA2, both of which are glycosylated proteins. While IgA1 is primarily found in serum and is known as Serum IgA, IgA2 is predominantly found in secretions and is referred to as Secretory IgA2.

IgA antibodies constitute 10 to 15% of the total antibodies. These antibodies are produced by the immune system in response to the presence of varied bacteria, viruses, or diseases in the body. However, due to certain health conditions, some people are not able to produce or produce very low amounts of IgA antibodies resulting in IgA deficiency, which can result in autoimmune disorders, leukemia, kidney disease, and intestinal diseases; while in some people due to certain health conditions like rheumatoid arthritis, lupus, cirrhosis, and hepatitis, the IgA antibodies levels are too high. This could be an indication of monoclonal Gammopathy that can transform into a type of cancer called multiple myeloma.

What Is Iga Test/ What Is Immunoglobulin A Test?

The Immunoglobulin Test or IgA test measures the amount of IgA antibodies in the blood. The IgA test can also screen for some autoimmune disorders and cancers. However, IgA tests lack specificity and cannot pinpoint the cause of IgA level fluctuations. They are used to assess antibody levels, and other tests are used in conjunction to determine the root cause of the issue.

Iga Pathology

Autoimmune and immune-mediated

IgA nephropathy – is caused due to IgA deposits in the kidney.

Celiac Disease – is caused by the presence of IgA anti-endomysial antibodies

Henoch–Schonlein purpura (HSP) – is a systemic disorder caused by IgA and complement component 3 deposits in the small vessels.

Linear IgA disease – Linear IgA disease is an IgA mediated immunoblots diseases

When Do You Take the Iga Test?

The Immunoglobulin Test is often advised by a doctor if the person is found to have infections, especially infections of the sinuses, lungs, stomach, or intestines. The IgA test is also given in the following conditions;

• Persistent Diarrheic
• Unintended weight loss
• Fevers having no relatable causes
• Skin rashes
• Allergies
• Illness after traveling
• HIV/AIDS or multiple myeloma
• IgA nephropathy symptoms

Iga Test Procedure

IgA test is performed to assess the immune function. The test requires blood samples to be drawn out from the veins of the forearm.

No special requirement is needed for the test.

Immunoglobulin A Normal Range

The IgA normal range differs with age and the IgA normal range for a healthy adult is between 80 – 350 mg/dL.

Immunoglobulin A Test Interpretation

If the Immunoglobulin A test shows a high level of IgA antibodies then it could be an indication of the following conditions;

• Allergies
• Chronic infections
• Autoimmune disorders like rheumatoid disorder, lupus, or celiac disease
• Liver Disease
• Inflammatory Bowel Disease
• Cancer such as lymphoma or leukemia

Low levels of IgA  could be indicative of the following conditions;

• Diabetes Complications
• Kidney Disease or Kidney Failure
• HIV/AIDS

High or low levels of Immunoglobulins do not necessarily mean the presence of any one of the above diseases and a doctor should be consulted for better interpretation of the test results.

Why Are IgA Tests Done?

Doctors may order an IgA test to diagnose problems with the immune system, intestines, and kidneys. They’re also done for kids who have recurrent infections. These tests can check for autoimmune conditions in which the body mistakenly makes antibodies against healthy tissues, such as arthritis, lupus, and celiac disease. Kids born with low levels of IgA — or none at all — are at higher risk for autoimmune conditions, infections, asthma, and allergies.

What is IgA deficiency?

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. Having an IgA deficiency means that you have low levels of or no IgA in your blood.

IgA is found in mucous membranes, mainly in the respiratory and digestive tracts. It is also found in saliva, tears, and breast milk. A deficiency seems to play a part in asthma and allergies. Researchers have also linked IgA deficiency to autoimmune health problems. These are health problems that cause your body’s immune system to attack your body by mistake.

What causes IgA deficiency?

IgA deficiency affects about 1 in 5 cases through familial inheritance, making it a genetic health problem. In rare instances, medications taken can also cause it.

What are the symptoms of IgA deficiency?

Most people with an IgA deficiency don’t have any symptoms of the health problem. It’s usually found on a blood test if it’s found at all. About 1 in 4 to 1 in 2 people with selective IgA deficiency will be affected. Some people with an IgA deficiency are more likely to get frequent infections. These can include sinus, lung, and digestive infections. Some people with IgA deficiency also are more likely to have allergies and digestive and autoimmune problems such as celiac disease or lupus.

What are the complications of IgA deficiency?

Potential complications can include:

• Diarrhea
• Sinusitis
• Bronchitis
• Eye infection
• Ear infection
• Pneumonia
• Autoimmune disorders
• Skin infection
• Asthma
• Allergic reactions to blood or blood product transfusions

Can IgA deficiency be prevented?

IgA deficiency is a problem that may be passed down through your family, so you can’t do anything to prevent it. But you can limit the spread of germs and sickness by washing your hands often and staying away from large crowds. This is especially true during cold and flu season. Also, talk with your healthcare provider about vaccines that may help prevent illness and when you should get them.

If you have IgA deficiency and are concerned about passing it on to your children, consult with a genetic counselor.

Key points

• Immunoglobulin A (IgA) is an antibody that’s part of your immune system. IgA is present in mucous membranes, specifically in the respiratory and digestive tracts. It also occurs in saliva, tears, and breast milk. “IgA deficiency, a hereditary health issue, can be passed down from family members.”
• Most people with an IgA deficiency don’t have any symptoms.
• There is no cure for IgA deficiency. Immunotherapy does not work to treat it.
• Complications for IgA deficiency include asthma, diarrhea, ear and eye infections, autoimmune diseases, and pneumonia.
• You can limit the spread of germs and illnesses by washing your hands often and staying away from large crowds.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your provider tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also, write down any new instructions your provider gives you.
• Understand the reason for prescribing a new medicine or treatment and how it can benefit you.. Also, know what the side effects are.
• Ask your healthcare provider if other treatment options are available for your condition. Understand the purpose of a recommended test or procedure and the potential implications of the results.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your provider if you have questions.