Immune suppression describes a loss of immune function. It can occur for many reasons, including disease, medication, surgery, age or genetics.
What is immune suppression?
Immune suppression, also known as immunosuppression or immunocompromise, means your immune system isn't working properly. So what is your immune system? It is a combination of defences our bodies have to fight off infections. Various parts of our body systems work as soldiers in this fight, particularly the white cells in our bloodstream, along with our spleen and lymph nodes.
When this system is suppressed, ie not working as it should, we are more vulnerable to infection.
What does it mean for me?
If your immune system is suppressed, you may be more vulnerable to infection. You are more likely to need to see a doctor, more likely to need antibiotics and more likely to land up in hospital for treatment if you develop an infection, than someone who is not immunosuppressed. You can't have live vaccines if you are immunosuppressed, and you may need to take special precautions when you travel.
You are also more vulnerable to certain skin cancers if you are immunosuppressed.
Do I need regular tests?
If you are on certain immunosuppressing medicines then you will have regular blood tests to check they aren't causing more harm than good. With others, tests will only be done if you develop a problem. Learn about monitoring of immunosuppressing treatments.
What is the immune system?
We are surrounded by millions of bacteria, viruses and other germs (microbes) that have the potential to enter our bodies and cause harm. The immune system is the body's defence against disease-causing microbes (pathogens).
The immune system is made up of non-specialised defences such as skin and the acidic juice produced by your stomach. However, it also has some highly specialised defences which give you resistance to particular pathogens. Another name for this resistance is immunity. These defences are special white blood cells called lymphocytes. Other types of white blood cells play an important part in defending your body against infection.
The lymphatic system is also part of the immune system. The lymphatic system is made up of a network of tubes (vessels) which carry fluid called lymph. It contains specialised lymph tissue and all the structures dedicated to the production of lymphocytes.
Where is the immune system found?
The immune system is generally divided into two parts. The first part is the defences you are born with. These form what are known as the innate system. The second part of your immune system, known as immunity, develops as you grow. Your immunity gives you protection against specific pathogens. Not only can this system recognise particular pathogens, it also has a memory of this. This means that if you encounter a certain pathogen twice, your immune system recognises it the second time around. This usually means your body responds quicker to fight off the infection.
The innate system is found in many different places around the body.
- First line of defence is your skin. Skin forms a waterproof barrier that prevents pathogens from entering the body.
- Your body cavities, such as your nose and mouth, are lined with mucous membranes. Mucous membranes produce sticky mucus which can trap bacteria and other pathogens.
- Gastric juice produced by your stomach has high acidity which helps to kill off many of the bacteria in food.
- Saliva washes pathogens off your teeth and helps to reduce the amount of bacteria and other pathogens in your mouth.
If bacteria or other pathogens manage to get through these first-line defences, they encounter a second line of defence. Most of these defences are present in your blood, either as specialised white blood cells or as chemicals released by your cells and tissues.
The second part of your immune system, the part that gives you immunity, involves the activation of lymphocytes. Lymphocytes are found in your blood and also in specialised lymph tissue such as lymph nodes, your spleen and your thymus.
What causes immunosuppression?
The following can be causes of immunosuppression:
- Age. Our immune systems become less effective when we become elderly.
- Persisting (chronic) disease. Immune systems tend to become less effective as certain long-term illnesses progress. Examples include severe chronic kidney disease, chronic liver disease and diabetes mellitus.
- Medicines for illness caused by the immune system attacking itself (autoimmune conditions). Examples include rheumatoid arthritis and Crohn's disease.
- Medicines in the form of oral steroids for conditions which result in inflammation where treatment is needed to reduce inflammation.
- Medicines taken to prevent rejection in people who have had organ or bone marrow transplants.
- Chemotherapy or radiotherapy treatment for cancer
- Cancers. Certain cancers can cause immune suppression, particularly those which involve the blood cells which are so crucial to our immune system. Lymphomas, leukaemias and myeloma are the cancers which may suppress the immune system.
- Not having a spleen, due to it having been removed. Or having a spleen which does not work well. This can occur due to certain conditions such as sickle cell anaemia, thalassaemia major or lymphoma, or after radiotherapy.
- HIV and AIDS. The human immunodeficiency virus (HIV) affects the immune system.
- Rare genetic conditions which result in loss of immune function - for example, severe combined immunodeficiency syndrome (SCID), DiGeorge's syndrome, Wiskott-Aldrich syndrome.
Which specific medicines cause immune suppression?
Oral steroids are a common offender and are used in numerous conditions. When used at high doses for long periods of time they can cause immune suppression. Lower doses do not generally cause a problem. For an adult, a dose of 40 mg per day of prednisolone for more than a week may cause immune suppression, but this dose varies for other steroids and for children. See separate leaflet called Oral Steroids for more information.
Other medicines which suppress the immune system include:
- Mycophenolate mofetil.
- Monoclonal antibodies - of which there are many ending in "mab", such as bevacizumab, rituximab and trastuzumab.
- Anti-TNF drugs such as etanercept, infliximab, adalimumab, certolizumab and golimumab. (TNF stands for anti tumour necrosis factor, and some of the "mab" medicines above act against TNF, so there is some overlap in groups of medicines here.)
These medicines are used to treat all sorts of conditions, some of the more common ones including:
- Cancers such as lymphoma or leukaemia.
- Rheumatoid arthritis.
- Crohn's disease.
- Ulcerative colitis.
- Organ transplants, to prevent rejection.
- Severe psoriasis and psoriatic arthritis.
Why would the spleen be removed?
Your spleen is an important part of your immune system but sometimes it has to be removed, with an operation called a splenectomy. This may need doing if you are involved in an accident, or have an injury where your spleen is ruptured. It may need removing to stop you losing vast quantities of blood.
Sometimes it has become too large and destroys too many of your blood cells. Examples where this occurs and the spleen may need to be removed include:
See separate leaflets called The Spleen and Preventing infection after a Splenectomy or if you do not have a Working Spleen for more information about the spleen.
What are the symptoms of immune suppression?
Much of the time, if you have immune suppression, you do not know you have it. However, you may be prone to getting infections more frequently. Also when you do get infections, they may be more severe and you may be more likely to develop severe complications. You may also get unusual or uncommon infections. For example, in general, healthy adults do not usually get thrush in the mouth, unless there is a good reason for it, such as using a steroid inhaler. For people with AIDS, however, thrush is common and may be very widespread or severe.
The medicines which can suppress your immune system may give you other side-effects. These vary and will be listed in the information which comes with your individual medicine.
What are the complications of immune suppression?
Infections can develop and spread particularly quickly in people whose immune systems are suppressed. A sore throat, for example, is more likely to develop into a chest infection. You are more likely to get spread of any one individual infection to your whole body (sepsis), which can make you dangerously ill.
People who have immunosuppression also seem to be at higher risk of certain types of skin cancer. This includes squamous cell carcinoma (SCC), melanoma and Kaposi's sarcoma. It is not entirely known for sure why this is. It may be because the immune system helps to destroy skin cells which have been damaged by the sun. These cells, if not removed by the immune system may go on to multiply and cause cancer. It may also be that viruses (such as human papillomavirus - HPV, or herpes viruses) involved in some cancers are more likely to be present if the immune system is suppressed. Some immune-suppressing medicines may directly affect skin cells in a way which makes them more likely to develop skin cancers.
If I have immune suppression, what symptoms should prompt me to see a doctor?
If you have immune suppression, the when-to-see-your-doctor rules change. With most minor infections, healthy people are encouraged to take a wait-and-see approach, treating the symptoms and only visiting the doctor if they feel very unwell or the infection is not settling on its own. If you have immune suppression, however, even a mild infection could become serious very quickly. So it is best to see a doctor as soon as possible rather than waiting to see how things go. Infections caught early can be treated quickly, preventing them from spreading and making you unwell. You are more likely to be given an antibiotic for a mild infection compared with someone who is not immunosuppressed, and it may well be in extreme cases that this might save your life.
So see a doctor if you think you might have an infection, such as a sore throat, a cough, symptoms of a urine infection, food poisoning, etc.
Seek urgent medical attention if:
- You have a high temperature (fever) over 38°C.
- You have chills or shakes (rigors).
- You feel generally unwell with dizziness or drowsiness or confusion.
- You have a rash.
- The light hurts your eyes.
- You have fits (seizures).
If you have a child who is immunosuppressed, all the above applies, but also seek medical attention urgently if your child is breathing rapidly, or not eating or drinking as normal.
Also keep an eye on your skin. If you develop any scaly areas which don't clear up quickly with a good moisturising cream, or if you have a new mole or one which has changed then see your doctor. Hopefully it won't be any kind of skin cancer, but if it is, the earlier it is treated, the better the outcome will be.
How is immune suppressant medication monitored?
This varies with the individual medication. Some medicines require you to have regular blood tests. These monitor your blood cells (white cells, red cells and platelets), and check that numbers aren't getting too low. There may also be blood tests to check the medication isn't affecting your liver or kidney function. For other immune-suppressing medication, you may have a regular blood test to see how well it is working. For example, if you take steroids for polymyalgia rheumatica (PMR), a blood test is done to check the levels of inflammation in your body. As these levels come down, the dose may be gradually reduced. If the blood tests show the disease is active again, you may need to increase the dose. Similar blood tests are done for monitoring of some of the medicines used to treat rheumatoid arthritis.
It may also vary over time. For example, for some medicines, such as methotrexate, you will originally need frequent blood tests every one or two weeks, whereas once you have been on them for a while, if things seem to be stable, this will drop to every three months.
Ask your GP or specialist about the monitoring requirements of your medication.
Are there any other tests?
Other tests may be needed for the condition for which you are having treatment. In some cancers, for example, bone marrow biopsy might be needed to monitor what is happening. In HIV and AIDS, specific blood tests on immune function may be used to monitor what is happening.
Your specialist may also monitor you for any changes in your skin, as immune suppression can make you more susceptible to skin cancers.
Other tests and monitoring requirements will depend on the specific medication. For example, if you take oral steroids, your weight and blood pressure may be monitored, as weight gain and high blood pressure can be side-effects of this type of medication. On steroids, your bone density will also be monitored, as they can cause 'thinning' of the bones (osteoporosis), and your eyes will be monitored for cataracts.
Can immune suppression be treated?
It all depends on the cause. In some cases it can be treated, in others it is managed. For example:
- HIV infection and AIDS are treated with specific anti-HIV medication. See separate leaflet called HIV and AIDS.
- Many cancers can be successfully treated, or at least their progression delayed, with chemotherapy.
- Stem cell (or bone marrow) transplants are used in some situations. Damaged cells are replaced with normal ones. This is used in some forms of cancer, as well as some genetic immunosuppression conditions.
- Immune suppression caused by medication should reverse if the medication is stopped. If the immune suppression is causing harm then sometimes an alternative can be used, or the dose dropped. In other cases, infection is quickly managed as and when it occurs, while the medication is continued. It depends on the condition being treated how long the medication is used for.
- If you have had a splenectomy, the effect is lifelong, but there are ways of reducing the risk of infection (see section below).
- In some conditions, such as genetic immune disorders, injections of antibody proteins (immunoglobulins) can be given to help the body fight infection.
Treating infections early is crucial if you are immunosuppressed. You will be given treatment for the infection. If you are unwell, or if it doesn't seem to be working, you may be admitted to hospital.
Do I need any specific treatments to prevent problems if I am immunosuppressed?
If your immune system is suppressed, the important thing is to take steps to avoid infection. This can be done in a number of ways:
- Take general steps to avoid infection. For example, avoid eating food which puts you at risk of food poisoning. Handle raw meat safely. Use general hygiene measures to keep your home, etc, clean and germ-free.
- Avoid close contact with people with infectious conditions where possible.
- Ensure all routine vaccinations are up to date. (Specific recommendations are made for immunosuppressed children having their childhood vaccinations.)
- Extra vaccinations for higher-risk people, such as an annual flu jab, and vaccination against pneumonia and shingles.
- Some live vaccinations (those which contain live germs) are not given to some people who have a suppressed immune system.
- Some people who have had a splenectomy and are at particular risk of infection are advised to take a regular antibiotic, such as penicillin, on a daily basis.
Are there any special precautions to take when I travel?
Because you are at particular risk of infection, it is wise to plan very carefully for travel. Have all travel vaccinations advised for your destination. (Depending on the reason for your immune suppression, you may be advised against certain live vaccines. Be wary of travelling to countries with high risk of diseases you cannot be vaccinated against.) Avoid going to places where you wouldn't have access to good medical care if you became ill. Travel with information about your condition and medication in case you need the help of a health professional while away from your usual doctor(s). Check your travel insurance covers you if you become ill. Discuss with your doctor and consider taking some "in-case" antibiotics and instructions for when to take them if you are at risk of specific infections. Take the usual precautions to avoid food poisoning/traveller's diarrhoea if visiting somewhere this might be a risk.
And finally, if travelling somewhere hot, use plenty of high-factor sun cream to protect your skin.
Further reading & references
- Immunisation against infectious disease - the Green Book (latest edition); Public Health England
- Immunosuppression; Travel Health Pro Fact Sheet
- Splenectomy; Public Health England, January 2015
- Wilsdon TD, Hill CL; Managing the drug treatment of rheumatoid arthritis. Aust Prescr. 2017 Apr;40(2):51-58. doi: 10.18773/austprescr.2017.012. Epub 2017 Apr 3.
- Yu SH, Bordeaux JS, Baron ED; The immune system and skin cancer. Adv Exp Med Biol. 2014;810:182-91.
- Skin cancer in transplant recipients; DermNet NZ
- Renal transplantation - immunosuppressive regimens for children and adolescents; NICE Technology Appraisal Guidance (2006)
- Moini M, Schilsky ML, Tichy EM; Review on immunosuppression in liver transplantation. World J Hepatol. 2015 Jun 8;7(10):1355-68. doi: 10.4254/wjh.v7.i10.1355.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Mary Harding
Dr Adrian Bonsall