Autism and the Immune System

Greetings Earthlings! 🙂

This week I’d like to discuss how the immune system can contribute to autism through inflammation and autoimmune diseases.

Really Aoife? I thought the immune system was supposed to protect me from illness and repair the body after injuries?

Yes- ordinarily the immune system functions to protect and heal us from injury and disease, however, dysfunctions in the immune system can cause serious health issues. There are three main categories of immune dysfunction:

• Immunodeficiency– where one or more parts of the immune system are inactive
• Autoimmunity– where an overactive immune system is unable to tell the difference between the cells of the body and foreign invaders like bacteria and viruses. This leads to autoimmune disease (such as rheumatoid arthritis) where the immune system attacks healthy cells causing disease
• Hypersensitivity– similar to autoimmunity where the immune system triggers an undesirable allergic reaction (like asthma and anaphylaxis) which attacks the cells of the body

So how does the immune system relate to autism?

A number have studies have highlighted that abnormal immune system activation could be playing a role in the development of autism. Inflammation is the body’s natural defense against foreign invaders. When the body is under attack from an infection for example, it starts to release pro-inflammatory chemicals called cytokines which triggers inflammation to start the battle. Once the threat has passed, an anti-inflammatory response begins to cool the body back down. This heating/cooling cycle doesn’t always run smoothly for some people leading to persistent inflammation which over time can cause damage to the body. Studies have shown that autists frequently show signs of widespread inflammation, often having high levels of pro-inflammatory chemicals. Postmortem brain samples in particular have shown evidence of enhanced immune activity suggesting that an overactive immune system may be contributing to the autistic brain.

There are also some studies that suggest autists are producing antibodies that attack their own brains- I know I’m my own worst enemy, but that is next level! 😛

Researchers believe that abnormal immune activity during pregnancy in particular could be a contributory factor in autism. Studies have noted that many women that have an autoimmune disease (such as lupus, psoriasis, diabetes etc.) also have a child with autism leading them to this potential link. It’s thought that pregnant women with autoimmune diseases produce antibodies that attack the baby’s brain as the immune system falsely identifies the baby as a foreign invader which can potentially cause autism and ADHD. Moreover, inflammation during pregnancy is also thought to interfere with the development of folds in the brain.

But is there any explanation as to why immune activity is abnormal in autism?

As with most things linked to autism, it’s likely that this activity has a genetic source. A number of the genes that have been linked to autism are also involved with the immune system, so mutations in these genes could explain the correlation.

Hope you enjoyed this post dear Earthlings!

Have a lovely weekend! 🙂

Aoife