What is an autoimmune disease?

Our immune system is responsible for protecting the body from foreign substances such as bacteria and viruses. The immune response is a tightly regulated process and is very important in keeping us fit and healthy.

Autoimmune disease occurs when the body recognises our own cells as harmful and initiates an inappropriate immune response. This leads to a wide variety of symptoms ranging from fatigue, muscle pain, and weight gain/loss to the destruction of body tissue.

How many autoimmune diseases are there?

There are over 80 different autoimmune diseases. Autoimmune disease does not describe a single disease but covers a huge variety of diseases that can affect almost any part of our body.

An autoimmune disease can affect specific parts of the body, such as coeliac disease where the lining of the small intestine becomes inflamed, and multiple sclerosis where the immune system attacks the nerve cells in the brain and spinal cord. But some autoimmune diseases can affect almost the entire body, such as lupus which affects the skin, heart, lungs and kidneys. Lupus sufferers can develop a distinctive characteristic butterfly-shaped rash over their cheeks and nose. Like many autoimmune diseases, the cause of lupus is poorly understood, and diagnosis can sometimes be difficult.

Interestingly, two of the most common thyroid diseases, Graves’ Disease and Hashimoto’s thyroiditis, are caused by an autoimmune response. In Graves' disease, the immune system produces antibodies that cause the thyroid to produce an excess of hormones. In Hashimoto's thyroiditis, the body attacks the cells in the thyroid gland leading to a decrease in the number of hormones produced.

Symptoms are often varied

As there are many different types of autoimmune disease, there is also a wide range of symptoms, but often the early symptoms can be similar and include:

• Swelling and redness
• Fever
• Numbness and tingling in the hands and feet
• Hairr loss
• Skin rashes

Individual autoimmune diseases also have their own unique symptoms. For example, Addison's disease causes low mood, decreased appetite and increased thirst. Hashimoto's disease on the other hand causes weight gain, fatigue and slowed heart rate. Some autoimmune diseases like psoriasis or rheumatoid arthritis (RA) cause flare-ups, where symptoms come and go.

Testing for autoimmune disease

In general, the diagnosis of an autoimmune disorder requires a combination of blood tests, a thorough review of symptoms and a physical examination. Autoantibody tests are useful to help diagnose an autoimmune disorder and in some cases, they can also be used to help evaluate the severity of the condition and monitor treatment. However, a diagnosis of autoimmune disease is never decided solely on the autoantibody results.

We spoke to Peter Prinsloo, Head of Clinical Governance here at Medichecks, about the limitations of testing for autoimmune disease:

'The issues with autoimmune testing vary from test to test but using lupus an example, the presence of anti-nuclear antibodies does not necessarily mean the individual will develop an autoimmune disease, in fact the majority of positive anti-nuclear antibody (ANA) tests are not associated with autoimmune disease (particularly at low levels). In some clinics, it has been reported that less than 10% of those with low to moderate positive ANA levels were diagnosed with an ANA-associated autoimmune disease. There is no absolute cut-off at which a positive ANA is clinically significant, however, the higher the ANA level the more likely it is to be associated with autoimmune disease. The same can be said for TTG antibodies when testing for coeliac disease (but also vice versa i.e. a negative test does not rule out that coeliac disease is absent).

Autoantibodies are a good screening tool to see if something is wrong in those with symptoms, or to confirm certain diseases, but an absence of these antibodies does not necessarily exclude certain diseases, nor does the presence of antibodies necessarily confirm an autoimmune disease. This is often seen with thyroid disorders where a positive antibody result does not necessarily equate to abnormal thyroid function, and abnormal function is quite often seen without any detectable antibodies.'

It is possible to have several different autoimmune diseases at the same time.

There is no single cause for autoimmune disease; our genes, environmental toxins and diet are all thought to contribute to the development of an autoimmune response. If we have an autoimmune disease this does not protect us from getting another, in fact, it increases the risk of further autoimmune diseases developing in our body. Because our genes are partly responsible for the development of autoimmune diseases, it is also common for multiple members of a family to suffer from an autoimmune condition.

Women are at a greater risk of developing an autoimmune disease

Autoimmune disease can affect any one of us but surprisingly nearly 80% of those who suffer from autoimmune diseases are women [1] and for lupus, in particular, more than 90% of sufferers are women [2]. Although there is no conclusive reason as to why this is, female sex hormones have been found to promote a woman’s immune response which leads to an increased likelihood of developing an autoimmune condition.

Diet and autoimmune disease

Our diet may affect the symptoms and progression of autoimmune disease

Currently, there is no cure for autoimmune disease and although certain medications can be effective at alleviating symptoms, diet is also thought to play a very important role. Improving our gut health and aiding digestion can help to manage symptoms and allow sufferers to lead healthy, active lives.

For those with an autoimmune disease, it is suggested that they reduce their intake of gluten, refined sugars and dairy as these food types can cause inflammation in the body. It is also advised that these food types are avoided as they can encourage flare-ups.

Blood tests

1. Thyroid Function Blood Test - a comprehensive test that looks for TSH, FT4 and FT3 - the more biologically active form of FT4. This test helps you to take a more in-depth look at your thyroid hormones.

2. Thyroid Function with Antibodies Blood Test - with this test, you can tell if your thyroid hormones are functioning within the healthy range. You can also detect any abnormalities caused by an autoimmune disease. Even if your thyroid function is currently normal, elevated antibodies may increase your risk of developing a thyroid disorder in the future.

3. Advanced Thyroid Function Blood Test - this test includes the thyroid hormones, thyroid antibodies, and nutritional markers that can support thyroid function. If your nutritional markers are low, this can cause symptoms like a thyroid disorder. For example, low iron (ferritin), low vitamin D and low B vitamins can cause fatigue and low energy.

Unsure which blood test is right for you? Head over to our thyroid buying guide. Or take a look at our pages to find out more about an overactive or underactive thyroid. 

References

1. Health.com. 2022. This May Be Why Women Are Far More Likely to Get Autoimmune Diseases. [online] Available at: <https://www.health.com/psoriasis/autoimmune-disease-women-genes> [Accessed 4 March 2022].

2. Medicalnewstoday.com. 2022. Lupus: Causes, symptoms, and research. [online] Available at: <https://www.medicalnewstoday.com/articles/323653.php> [Accessed 4 March 2022].