What Is IgAN?
Everyone’s immune system is made up of antibodies that help identify and remove things that can cause infection. There are numerous kinds of antibodies, including one kind called IgA. They are among those proteins circulating in your bloodstream. When your body makes too much IgA or the IgA is made incorrectly, it could lead to IgA nephropathy.
Immunoglobulin A nephropathy (IgAN), also called Berger’s disease, is a progressive, long-lasting autoimmune disease that attacks abnormally high levels of a specific type of IgA protein. This can result in kidney damage and function decline.
With almost 13 out of every million people in the United States diagnosed per year, IgAN is one of the most common autoimmune kidney diseases.
What's Behind IgAN?
Your kidneys work a lot like a coffee filter.
Much like separating grounds from coffee, your kidneys act as filters that remove waste that is in your blood. If your kidneys aren’t working as they should, substances like protein can leak into your urine. When this happens, it’s called proteinuria.
When you have IgAN, your body produces abnormally high levels of a specific type of IgA protein. Your immune system then attacks these proteins, causing them to form clusters that accumulate in the kidneys.
How Can IgAN Damage Your Kidneys?
IgAN is a heterogenous disease, meaning each patient's journey is different.
In the kidney
IgA clusters can leave deposits in the kidneys, which can cause inflammation and the body’s defense system to react by activating multiple systems and pathways in your body.
There are multiple systems and pathways involved in IgAN that can damage your kidneys, some of which include:
The endothelin A (ETA) pathway
Normally, this pathway is involved in regulating multiple functions in the kidney like blood pressure and balancing concentrations of salts and fluid. When the ETA pathway is activated in IgAN, it can lead to kidney damage and scarring through various processes. As a result, protein may leak into the urine.
The complement system
Normally, this part of your immune system helps fight viruses and bacteria. When you have IgAN, the complement system can become overactivated in your kidneys. This may result in inflammation, injury, and proteinuria.
Kidney inflammation and scarring
When certain cells in the kidneys are damaged, additional signaling could occur. Those signals form a loop that may further increase inflammation and scarring.
Disease progression
Although progression of IgAN varies, inflammation, scarring, and damage may eventually cause the kidneys to fail, and dialysis or a transplant may be needed.
