About IgAN
What is IgA nephropathy (IgAN)?
Immunoglobulin A nephropathy, also known as Berger disease, IgA nephropathy, or IgAN, is a rare, progressive autoimmune disease thought to start in the gut. IgAN occurs when the IgA antibody complexes deposit in the kidney, causing inflammation and damage. The disease impacts ~100,000 people in the United States.
The course of IgAN is highly unpredictable. IgAN can cause chronic kidney disease (CKD) and end-stage renal disease (ESRD) and can result in the need for a kidney transplant. Because IgAN is often asymptomatic in early stages, people may go undiagnosed until kidney damage has already occurred.
Proteinuria and estimated glomerular filtration rate (eGFR) are key ways to determine kidney health and function. Monitoring your levels can allow for early intervention before kidney scarring and irreversible damage occur.
How does IgAN happen?
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.
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.
For many people, the first signs of IgAN include
Bloody or frothy urine
Lower back pain
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.
This is not something that you have to go through alone, and you can save yourself a lot of trouble, stress, and potential negative impacts on your health by getting involved earlier on in your kidney journey.
— Chris, a person living with IgAN
Terms to know
When it comes to IgAN, a lot of the related terms can be challenging to remember or understand. With that in mind, we’ve listed some of the most important words and what they mean below.
Antibodies
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.
Autoantibodies
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.
Biopsy
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.
Estimated glomerular filtration rate (eGFR)
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.
Ileum
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.
Immune complexes
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.
Peyer’s patches
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.
Proteinuria
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.
Renin-angiotensin system
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.
Renin-angiotensin system inhibition (RASi)
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).
Urinalysis
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.
Urine protein-to-creatinine ratio (UPCR)
This urine test is used to measure protein in the urine and can be used to monitor kidney function and detect kidney damage.