What are autoimmune diseases?
The immune system is your body’s natural defence system. It identifies and protects against anything foreign to the body, including bacteria, viruses, toxins and other people’s blood or body tissue.
Sometimes something goes wrong – the immune system attacks healthy body cells by mistake, causing an autoimmune condition.
There are many well known autoimmune diseases, including multiple sclerosis and type 1 diabetes. PBC is an autoimmune condition where the immune system attacks the cells of the bile ducts in the liver.
Find out more about autoimmune disease
Who gets autoimmune conditions?
We don’t fully understand why some people get an autoimmune condition and others don’t. In PBC, there seems to be some genetic link. Close relatives of someone with PBC have roughly 10 times the average risk of developing it themselves.
Remember – PBC is a rare condition. Having 10 times the risk sounds a lot, but it’s a very small risk to start with so the risk to relatives is not as great as it seems.
In people who do have a genetic risk of PBC, it’s likely that the disease is triggered by something they’ve come into contact with in the environment. For example, an infection, tobacco smoke or contact with some types of chemicals, including those in nail varnish and hair spray.
A link with autoimmune hepatitis
Autoimmune hepatitis (AIH) is another autoimmune disease of the liver. The immune system attacks liver cells (rather than the cells of the bile ducts, as happens in PBC).
Some people develop AIH on its own. But it is also linked to PBC. Around 1 in 10 people with PBC also have some degree of AIH. Your doctor will be able to tell this from your test results.
There is more about AIH in people with PBC in the section on diagnosing PBC. Read more about AIH and about autoimmune conditions in general.
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Published: October 2024
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