IgAN Connect | What is IgA Nephropathy (IgAN)?

About IgAN

What is IgA nephropathy (IgAN)?

Immunoglobulin A nephropathy, more commonly called IgA nephropathy or IgAN, is a chronic autoimmune disease. Although it’s often referred to as a kidney disease, it is actually thought to start in the gut.

And while it may not start in the kidneys, IgAN can lead to chronic kidney disease, end-stage kidney disease, and even kidney transplant. In fact, more than half of people with the disease may progress to end-stage kidney disease within 20 years of the initial diagnosis.

For many people, the first signs of IgAN include:

Kidney Illustration

Bloody or frothy urine

Lower back pain

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Swelling in the hands or feet

These are only some of the initial symptoms that may occur.
If IgAN is suspected, a kidney biopsy is needed in order to confirm the diagnosis.

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Helpful questions to ask your doctor

“What are some things I should know about my IgAN diagnosis?”

“Are there any other symptoms I should expect?”

“What does this diagnosis mean for me in the future?”

“How often will I need to see a doctor and monitor my progress?”

How does IgAN happen?

IgA1 antibody

IgAN is caused by increased levels of a type of IgA1 antibody, called a galactose-deficient IgA1 antibody.


This antibody is thought to be formed in the gut. In people with IgAN, more of this type of antibody appears in the blood than normal, leading to an autoimmune response.

Antibody clusters

This response causes the immune system to react, resulting in the formation of clusters of antibodies called immune complexes.


Those immune complexes become trapped in the kidneys, which can lead to kidney inflammation and damage.

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Did you know?

IgAN is more likely to occur in men than in women

Many medical experts believe that IgAN starts in the gut, where IgA1 is produced

IgAN is considered a rare disease, and it affects less than 150,000 people in the United States

Terms to know

When it comes to IgAN, a lot of the related terms can be challenging to pronounce, remember, or understand. With that in mind, we’ve listed some of the most important terms and what they mean below.

Antibodies are made by cells in the immune system called “B cells.” When the body recognizes something that does not belong, such as bacteria, viruses, or toxins, B cells make antibodies that attach to it and help the body remove it. Another name for antibody is immunoglobulin.

A biopsy is a procedure in which a sample of cells or tissue is removed from the body to be examined by a pathologist. If IgA nephropathy is suspected, a kidney biopsy is needed to determine a diagnosis.

Peyer’s patches are areas of lymphoid tissue, like tonsils, lymph nodes, or the spleen, that play a large role in the immune system. They monitor for things that do not belong in the intestines and help destroy them if needed. Peyer’s patches are a main site of the immune cells that make the antibodies thought to contribute to IgA nephropathy.

Autoantibodies are antibodies that attack a person’s own body. Normally, the immune system, including antibodies, will ignore normal tissues. Autoantibodies will do the opposite and target a normal part of the body for destruction by the immune system. Some autoimmune diseases, such as IgA nephropathy, are caused by autoantibodies.

When there are increased levels of protein in the urine, this is called proteinuria. It can happen when the kidneys are inflamed or damaged. Measuring proteinuria levels in people with IgA nephropathy is a way to see if the kidneys show signs of potential damage. Typically, proteinuria is measured through a urinalysis.

Estimated glomerular filtration rate or eGFR is a measure of how well your kidneys are functioning and filtering blood. It is measured by a blood test.

The renin-angiotensin system (RAS) is used by the body to help control blood pressure. The body monitors for things like changes in blood pressure to the kidneys and salt content in the blood. Depending on these factors, the body can increase blood pressure.

The ileum is the last part of the small intestine. It connects to the first part of the large intestine, called the cecum. The ileum helps to further digest food coming from the stomach and other parts of the small intestine. It is also where the majority of Peyer's patches are located in the gut.
Medications like angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) can be used to block the RAS to help decrease blood pressure and protect the kidneys from damage that can be caused by high blood pressure. This process is called RAS inhibition (RASi).

When antibodies bind to their target, they form an immune complex. There can be more than one antibody or antigen in the complex. In diseases like IgA nephropathy, immune complexes can cause damage to the kidneys.

This is a test of the urine. It can check for many things, including color, odor, pH, blood, protein, glucose, bacteria, cells, and other substances. If you are living with IgA nephropathy your doctor will conduct this test on an ongoing basis to determine the best treatment plan for you.  

This urine test is used to measure protein in the urine and can be used to monitor kidney function and detect kidney damage.

Find out more about current management approaches and the goals of IgAN treatment.