How to Normalise an Overactive Immune System

The immune system is a complex system composed of a variety of organs and cell types. It fights against invading pathogens and destroys them to prevent harm to your body. However, sometimes things can go wrong, and the immune system can stop working as it should. For example, it can become overactive and cause asthma and allergies, it can become misdirected which can lead to autoimmune diseases, or it can become unresponsive, causing immunodeficiencies.

An autoimmune disease involves the immune system not recognising the body’s own cells, instead mistaking them for invaders and attacking them. This can lead to many negative consequences.

The importance of immune modulation

The term ‘immune modulation’ describes the process of either suppressing or stimulating the immune system, in order to make it function properly. Immune modulation is usually looked at from two different perspectives:

  • Cancer immune modulation: enhancing the immune system to detect and kill tumour cells. The idea of immune modulation for cancer has gained a lot of attention in recent years, allowing immunotherapy to be used to target specific cancers
  • Autoimmune disease immune modulation: improving the body's tolerance of its own cells, without suppressing the whole immune system1 

About our immune system’s cells

The immune system can be divided into innate immunity and adaptive immunity. Innate immunity is the first line of defence against invading pathogens and is non-specific, meaning it provides general protection. Examples include physical barriers, such as the skin. 

Adaptive immunity is specific and more effective, given that it’s designed specifically to attack a certain pathogen. Two components of the adaptive immune response primarily cause autoimmune disorders. These include:

  • T cells: this cell type can be categorised into T-helper cells, which assist other immune cells in the killing of pathogens, and cytotoxic T cells, which kill infected cells to prevent the spread of infection
  • Antibodies: these are proteins rather than a cell type; they are specifically designed to attach to the pathogen, marking it for destruction by the rest of the immune response

What is an autoimmune disease?

Autoimmune diseases are caused by a failure of tolerance mechanisms, which protect our tissues from destruction by our own immune system. If T cells or antibodies cannot correctly recognise our own cells, they can cause cell death and organ damage.

Autoimmune diseases can be caused by self-reactive antibodies (autoantibodies) or self-reactive T-cells. Other parts of the immune system may occasionally contribute, but these two components are the main culprits. 

The incidence of autoimmune diseases is on the rise, and they are more common in females.

There are over 80 identified autoimmune diseases, which can be described as organ-specific (affecting a particular organ only) or systemic (affecting a whole organ system).

How do we normalise an overactive immune system?

Normalising an overactive immune system involves many components, depending on the risk factors and triggers involved:

  • Special diets: with autoimmune diseases such as coeliac disease, certain foods may be a trigger for the condition. Avoiding these foods reduces the chance of flare-ups and symptoms; in the case of coeliacs, following a gluten-free diet
  • Avoid promoting inflammation: excess stress and inflammatory foods can increase the presence of pro-inflammatory markers. These can in turn increase inflammation, exacerbating symptoms
  • Healthy lifestyle: eating a balanced diet, staying hydrated, and getting good quality sleep helps the immune system stay in good shape. These simple acts allow the immune system to function correctly and allow it to attempt to rebalance itself

The most common autoimmune diseases & their symptoms

Currently, the most common autoimmune disease is ‘Long COVID’, but this condition can affect patients very differently and is still being researched. Below are some of the most common autoimmune diseases:

Coeliac disease 

Found in approximately 1% of the population, coeliac disease is an autoimmune disease triggered by the consumption of gluten - the protein component found in wheat, barley and rye. 

Coeliac disease is thought to be caused by both genetic and environmental factors:

  • Genetic: The HLA-DQ2 variation of the HLA gene (which is linked to the immune system) is found in 95% of individuals with coeliac disease. However, it is also found in 30-40% of the total population. Although this shows an association between coeliac disease and the HLA gene, it is not the only cause. 
  • Environmental: The environmental component is the consumption of gluten, which contains amino acids that cannot be fully digested by humans. The partially-digested amino acid products trigger the innate and adaptive immune responses in the small intestine, damaging healthy tissue2 

Coeliac disease causes a range of gut symptoms, given that it affects the small intestine:

  • Diarrhoea
  • Stomach cramps
  • Bloating and wind
  • Indigestion
  • Constipation

It can also cause general symptoms, some of which are extremely uncommon:3

  • Fatigue
  • Weight loss
  • Itchy rash
  • Infertility
  • Nerve damage
  • Disorders affecting coordination, balance, and speech

Crohn’s disease

Using the term ‘autoimmune disease’ for Crohn’s disease is widely debated, as it isn’t caused by the immune system attacking the body’s tissues. Instead, it is an attack on the healthy gut bacteria in the digestive system. Because of this, it tends to be referred to as an ‘auto-inflammatory condition.’ 

It is a type of inflammatory bowel disease, in which the tissues of the gut become inflamed. It commonly involves the small intestine and often spreads into the bowel tissues. 

Symptoms can vary in severity, and people may experience periods of no symptoms at all. These typically include:4

  • Diarrhoea 
  • Fever-like symptoms
  • Fatigue
  • Abdominal cramps and pain
  • Blood in stool
  • Mouth sores
  • Reduced appetite
  • Weight loss
  • Anal fistula 

This condition is diagnosed via blood and stool tests, as well as using a colonoscopy to view the entire colon. Other visualisation techniques may also be used.5 

Autoimmune thyroiditis (Hashimoto’s)

This autoimmune disease is organ-specific and targets the thyroid: the gland located at the base of the neck. It releases thyroid hormones, which regulate many processes within the body. Hashimoto’s leads to hypothyroidism (underactive thyroid), which can lead to many further complications including high cholesterol, high blood pressure, heart disease, and heart failure. 

The symptoms of Hashimoto’s are:

  • Enlarged thyroid (goitre)
  • Fatigue
  • Weight gain
  • Difficulty tolerating cold
  • Joint and muscle pain
  • Constipation
  • Dry skin or dry, thinning hair
  • Heavy or irregular menstrual periods
  • Slowed heart rate

This condition is diagnosed via a blood test for the thyroid hormones, as well as a physical exam to look for the goitre and other signs.6 

Type 1 diabetes

This is an organ-specific autoimmune disease affecting the pancreas, in which insulin-producing beta cells are attacked. This form of diabetes is mainly diagnosed before the age of 14, via blood glucose tests, as Type 1 diabetes causes increased blood glucose levels. This condition has potentially serious consequences, but it can be treated using daily insulin injections. 

A variety of immune cells can contribute to the destruction of beta cells in diabetes patients: cytotoxic T cells, autoantibodies and macrophages.

Symptoms of type 1 diabetes:7 

  • Constantly feeling very thirsty
  • Frequent urination, especially during the night
  • Fatigue
  • Unexpected weight loss 
  • Recurrent thrush
  • Blurred vision
  • Cuts and grazes that won't heal
  • Fruity-smelling breath

Multiple sclerosis

Commonly abbreviated to MS, this autoimmune disease arises due to auto-reactive T cells attacking the myelin sheath (insulating layer) that surrounds nerve fibres and the spinal cord. Patches of the myelin sheath become inflamed, which disrupts messages travelling along the nerves; they may become delayed, redirected, or stop completely.

The causes of MS are unknown, but include genetic risk factors and certain viral infections, potentially due to ‘molecular mimicry.’ This concept involves the immune system attacking the myelin sheath because it mimics the structure of viral proteins that it has encountered before.

The symptoms of MS vary significantly between patients, and can also vary between periods of time. The most common symptoms include:8

  • Fatigue
  • Sight problems, such as a temporary loss of vision
  • Numbness and tingling
  • Muscle spasms, stiffness, or weakness
  • Pain 
  • Difficulty with thinking and learning
  • Mental health decline
  • Bladder or bowel problems
  • Difficulties with speech or swallowing 

Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, progressive condition that affects the joints in both sides of the body. The inflammation of the membrane surrounding the joint eventually wears down the cartilage, which would normally act as a shock absorber in the joints. 

The symptoms of RA include:

  • Pain, swelling, or stiffness in the joints 
  • Morning joint stiffness 
  • Fatigue
  • Weakness
  • Fever-like symptoms 

Like other autoimmune diseases, RA also has environmental and genetic risk factors. Some variations of the HLA genes make individuals more susceptible to the condition. 

It is diagnosed using scans such as X-rays, as well as blood tests to look for signs of inflammation.9

When to see a doctor

If you experience the symptoms of any of these autoimmune conditions, it is important to contact your doctor. They can then refer you to specialists for the particular autoimmune disorder in order to get the right diagnosis and management plan for your condition.  


The complexity of the immune system means that occasionally things can go wrong. Autoimmune diseases, in which the body attacks its own tissues in error, may develop as a result. This causes a host of symptoms that require urgent diagnosis in order to manage the condition. 

Although there is no cure, the overactive immune system can be managed to some extent to reduce symptoms. This can be achieved by avoiding triggers such as stress and pro-inflammatory foods, as well as maintaining a healthy lifestyle.


  1. Liebman HA. Immune modulation for autoimmune disorders: evolution of therapeutics. Semin Hematol. 2016 Apr;53 Suppl 1:S23-26. Available from: 
  2. Denham JM, Hill ID. Celiac disease and autoimmunity: review and controversies. Curr Allergy Asthma Rep. 2013 Aug;13(4):347–53. Available from: 
  3. Coeliac disease [Internet]. NHS. 2017 [cited 2022 Sep 3]. Available from: 
  4. Crohn’s disease - Symptoms and causes [Internet]. Mayo Clinic. [cited 2022 Sep 3]. Available from: 
  5. Crohn’s disease - Diagnosis [Internet]. Mayo Clinic. [cited 2022 Sep 3]. Available from: 
  6. Hashimoto’s disease [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases. [cited 2022 Sep 3]. Available from:
  7. Type 1 diabetes – Symptoms and getting diagnosed [Internet]. NHS. 2022 [cited 2022 Sep 3]. Available from: 
  8. Multiple sclerosis - Symptoms [Internet]. NHS. 2017 [cited 2022 Sep 3]. Available from: 
  9. Rheumatoid arthritis (RA): causes, symptoms & treatment FAQs [Internet]. Cleveland Clinic. [cited 2022 Sep 3]. Available from: 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Aisha Yasin

Biomedical Science - Biomedical Sciences, General, Lancaster University, England

"I am a recent biomedical science graduate, with ambitions to go on to do post-graduate medicine. During my biomedical science degree I have done a variety of modules including anatomy, physiology, clinical biochemistry and many more... Currently working as a healthcare assistant for P&O Cruises"

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