Immune system diseases: the enemy within

Patsy Westcott / 22 October 2018

The immune system provides an arsenal of weapons against infections. But if this finely tuned system goes awry, our own bodies can come under attack.



Like 3% of women aged 50-plus, a few years ago I was diagnosed with Hashimoto’s disease, an underactive thyroid. The disease, which causes weight gain, constant chilliness, dry skin, thinning hair, fatigue and just feeling not that great, is one of more than 80 autoimmune (AI) conditions, in which the immune system mistakenly attacks the body’s own tissues.

AI diseases are the third most common type after heart disease and cancer. And they are on the rise. The good news is, greater understanding of how the immune system works is leading to new treatments with fewer side effects and better quality of life for the 5-10% of us affected.

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What causes autoimmune diseases?

When Professor David Wraith, director of Birmingham University’s Institute of Immunology and Immunotherapy, began studying autoimmunity 35 years ago, scientists were puzzled as to what was going on. ‘Why would a system, which had evolved over millions of years to fight infections, turn against itself?’ he asked.

The answer turned out to lie in the cunning ability of the immune system to generate and send out armed forces – in the form of T cells and the B cells that make antibodies – on a search-and-destroy mission for invaders, while sparing the body’s own cells. In autoimmunity, the ability to distinguish ‘self’ cells from foreign invaders gets scrambled and causes a misguided attack on the body’s own tissues. 

Once this mistake has been made, any part of the body can come under friendly fire. Examples include the pancreas (causing Type-1 diabetes), thyroid (Hashimoto’s and Graves’ disease, which causes an overactive thyroid), central nervous system (multiple sclerosis – MS),  the skin (psoriasis) and the hair follicle (alopecia areata, which causes thinning hair), to name a few. Other AI diseases attack multiple tissues and organs: lupus – aka systemic lupus erythematosus (SLE) – for instance, affects the skin, joints, heart, lungs and nervous system. And rheumatoid arthritis (RA) affects not just joints, but eyes, lungs, skin, heart, blood vessels and other organs.

Do autoimmune diseases run in the family?

So why does the immune system go into a self-harming overdrive in some of us? ‘It’s largely down to genes,’ says Professor Wraith. ‘There is a vast spectrum of different gene combinations involved in regulating the immune system, which set the bar – or threshold – to autoimmunity at a higher or lower level.’

This explains why AI diseases often cluster in families. My paternal grandfather and uncle had Type-1 diabetes, a cousin on the same side, MS, while my elder daughter has Hashimoto’s.

Autoimmunity is especially common in women. Nine out of ten lupus sufferers are female, for example. It’s not known exactly why, but Professor Wraith suggests that evolution programmes women to have a stronger immune response to keep them healthy during their reproductive years.

Environmental factors and autoimmune diseases

But while our genes play a role, our environment undoubtedly does, too. In twins with a risk of MS separated in early life, for instance, those who move to sunnier climes have a lower risk. Low sun exposure has also recently been linked to a higher risk of other immune-mediated diseases, such as Crohn’s disease and ulcerative colitis.

Infections are another potential culprit. The Epstein-Barr virus (EBV), best-known for causing glandular fever, is associated with many conditions, including lupus, MS, RA and autoimmune thyroid disease. Other infections could be offenders too, although it’s hard to pinpoint specific ones as they may have been so mild as to pass unnoticed.

‘It’s thought that infectious agents may mimic the body’s own proteins, so setting off an immune response,’ explains Simon Davis, professor of molecular immunology at Oxford University’s Radcliffe Department of Medicine.

Just to complicate matters, however, certain infections may actually prime the immune system to function as it should, especially if we come across them in childhood. High standards of hygiene and healthcare, which limit our exposure to infections and parasites in early life, may be culpable, according to the so-called hygiene hypothesis.

What part does lifestyle play in autoimmune diseases?

Prolonged stress, smoking, inactivity and poor sleep are also linked to an increased risk of AI conditions and with greater severity of symptoms, as is a high-fat, high-salt Western diet and obesity. Research suggests that, for example, the chemicals released by fatty tissue trigger chronic, low-grade inflammation, impacting on immune cells called regulatory T cells, key players in the immune system that help stop the body attacking its own cells.

Do gut bacteria have a role in autoimmune diseases?

As so often nowadays, attention has recently turned to the potential role of the gut microbiota – the community of bacteria and other microorganisms that lives in our intestines – in lupus, MS and other AI diseases. Says Anne Cooke, vice president of the British Society of Immunology and professor of immunobiology at the University of Cambridge: ‘People with autoimmune diseases have a more restricted range of bacteria and other organisms, not just in the gut but on the skin and in the nose, but whether this is a cause or effect we don’t yet know.’

Learn more about what gut bacteria can do for your health

Treatment for autoimmune diseases

This mainly involves managing symptoms: steroid medications to help to quell inflammation, tamping down an overactive immune system with immunosuppressant drugs, as well as easing symptoms caused by autoimmune tissue damage. Until fairly recently, such treatments have tended to be heavy handed, quelling the whole immune system, and so increasing the risk of side effects – from higher risk of infections to a higher risk of cancer.

However, this is changing as Dr Consuelo Anzilotti, specialist registrar in immunology at Oxford’s John Radcliffe Hospital, explains: ‘We are at an exciting time as treatment options are really opening up’. She points to the advent of ‘biologics’, medications tailored to seek and destroy specific components of the immune system, giving patients – and doctors – more choice.

‘There is no one size fits all. Patients need to work with a specialist so, if one medication doesn’t work, another can be tried,’ she says.

Even more sophisticated treatments designed to reset an immune system that has lost its sense of self are in the pipeline. One such, an injected medication administered fortnightly, has been shown to be safe and effective in early trials of Graves’ disease and MS, for example. The hope is that in future it may even be possible to vaccinate those at risk of AI conditions to prevent them altogether.

Says Professor Wraith, ‘We’re on the brink of a new era with new medications designed to restore the immune system’s ability to recognise ‘self’; when I started no one would have believed this to be possible, but now it is within sight.’

5 ways to help yourself

1. Eat right 

A healthy, plant-based Mediterranean diet helps ease chronic inflammatory disease according to research.

2. Don’t smoke

Smoking is one of the biggest risk factors for AI diseases.

3. Sleep well 

Your immune system needs a good night’s rest. Chronic insomnia is linked to a 70% higher risk of
AI disease.

4. Moderate alcohol

Alcohol is processed by the liver: if you are taking prescription medications, it puts an extra strain on that organ.

5. Make friends with your doctor 

Treatment is ongoing, so finding a doctor you trust is vital, says Dr Anzilotti.




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