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, it can lead to chronic kidney disease, end-stage kidney disease, and even kidney transplant. In fact, more than half of patients may progress to end-stage kidney disease within 20 years of initial diagnosis.
For many people, the first sign of IgAN includes:
Bloody or frothy urine
Acute nausea or vomiting
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.
Helpful questions to ask your doctor
How does IgAN happen?
In people with IgA nephropathy, more IgA1 antibodies enter the bloodstream than normal. When this happens, IgA1 can build up in the kidneys and lead to inflammation and damage.
There are treatment options available that may be right for you
Did you know?
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.
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 IgAN.
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 IgAN, are caused by autoantibodies.
Increased levels of protein in the urine; this can happen when the kidneys are inflamed or damaged. Measuring proteinuria levels in patients with IgAN is a way to see if the kidneys show signs of potential damage. Typically, proteinuria is measured through a urine analysis.
Estimated glomerular filtration rate (eGFR)
This is a blood test that is used to measure how well the kidneys are functioning and filtering blood.
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 blood. Depending on these factors, the body can increase blood pressure.
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 the location of Peyer’s patches.
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 the damage that can be caused by high blood pressure. This process is called RAS inhibition (RASi).
When antibodies bind their target, they form an immune complex; there can be more than one antibody or antigen in the complex. In diseases like IgAN, immune complexes can cause damage to the kidneys.
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.