When the Body Rebels Against Itself

by H Nixey Upper Sixth

Your immune system ‘rebels’ against all kinds of nasties, known as pathogens, including viruses, bacteria and fungi...

...But what happens if your immune system decides to turn on you, and ‘rebel’ against your own body? Answer: Autoimmune disease

Autoimmune diseases occur when the immune system mistakenly attacks healthy body cells because it mistakes them for foreign cells such as pathogens; for example, in Type 1 diabetes the body produces an autoimmune response against β cells, in the pancreas, damaging them and preventing them from producing insulin, a hormone that is responsible for controlling blood sugar. Other autoimmune diseases include Lupus, where the body produces far too many antibodies and Multiple Sclerosis (MS), where the immune system attacks the nervous system. More specifically, the immune system of an MS sufferer will attack a protective coating called the myelin sheath which surrounds the nerves. Consequently, this coating becomes damaged and, without this protective ‘shield’, the nerves themselves may also become damaged. It is this nerve damage which causes symptoms, as it causes nervous signals that would normally travel along the nerves to be slowed or disrupted.

It’s often said that we are all different and unique; quotes such as “no one is you and that is your power” and “why fit in when you were born to stand out?” paint this individuality as a positive thing, which indeed it is. Our differences enrich us and besides, if everyone was the same, life would be boring, right? However, in terms of autoimmune diseases, the fact that no two people suffering from certain autoimmune disorders (like MS and Lupus) present in the same way, or with the same symptoms actually presents doctors with a big challenge.

For example, although the two main symptoms of Lupus are extreme tiredness and joint and muscle pain, the severity of these symptoms can vary hugely, and other possible symptoms include (but are not limited to) headaches, anaemia, sensitivity to light which causes rashes, depression, hair loss, fever, and dry mouth and eyes…not everyone with Lupus will experience all of these symptoms but rather a unique combination of them. Furthermore, many of these symptoms are symptoms that are fairly common and can be caused by other illnesses or even lifestyle

choices. The fact that many of these symptoms are so commonly caused by other things often leads to doctors failing to recognise that someone is suffering from the condition, instead dismissing it as something else. Unfortunately, this makes it really difficult to get a diagnosis and many cases of Lupus therefore go undiagnosed for prolonged periods, which can occasionally lead to more serious problems including organ damage.

Although allergies are not actually autoimmune disorders, they do have some parallels with this type of condition because they too are caused by a fault with the immune system. When someone has an allergy, their immune system recognises harmless substances (such as nuts) as dangerous invaders, prompting it to overreact and launch a full on ‘rebellion’ against the allergen. This then causes a reaction. These reactions are normally mild, for example sneezing, rashes, or a runny nose; a more severe reaction known as anaphylaxis is rare, although not uncommon.

By reading this far, you have probably gathered that autoimmune disorders are fairly complex conditions. But what causes them? Unsurprisingly, the answer to this question is also complex, and scientists and doctors do not yet have all the answers!

They may not know exactly what causes the immune system to rebel against the body in this way, however they do have some theories, and believe that a mix of factors contribute; for example, if you have a family member affected by a particular autoimmune disease, scientists believe this slightly increases your risk of developing that particular disease or another autoimmune disease, and there is research to suggest that variations in the BACH2 gene appear to have links to both allergies and autoimmune conditions. Conversely, there is some evidence to suggest that hormones play an important role in the development of autoimmune disease; nearly 80% of people with these conditions are women, and in a majority of cases, these conditions develop at the childbearing age (15-44,) when women’s hormone levels are higher. According to John Hopkins Medicine, there are several other theories about reasons for these conditions to develop, though they are not proven. One of these theories is that, following infection with a virus or even cancer, healthy body cells can get caught in a leftover inflammatory immune response that was originally intended to fight off the infection or cancer. Another of these possible theories is the ‘damage theory’, which speculates that, when parts of the body (e.g a runner’s heel) are subjected to high stress, the tendon damage that occurs leaves tissue that shouldn’t normally be exposed in contact with blood. This is almost like a small wound, and, when the immune system tries to heal it, an abnormal immune response may occur, possibly leading to an autoimmune disease known as psoriatic arthritis.

Research is always ongoing to find better treatments. Despite there currently being no cure for many of these conditions, scientists have developed treatments to manage them and dampen their effects, and, thanks to this, many sufferers do indeed lead fairly normal lives.

Yes, the immune system may sometimes be a rebel, but, to be honest, it’s a good thing it is, as this means it can protect us from infectious disease and illness. Most of the time, we have a lot to thank it for!