Immune System Disorder

Your immune system is your body’s defense network, but when it malfunctions, it can attack your own healthy cells, fail to protect you from germs, or overreact to harmless substances. These immune system disorders affect millions of people and can range from mild to life-threatening conditions.

Table of contents

• What Is an Immune System Disorder?
• How Your Immune System Works
• Types of Immune System Disorders
• Autoimmune Diseases
• Immunodeficiency Disorders
• Overactive Immune System
• What Causes Immune System Disorders?
• Common Symptoms
• How Disorders Are Diagnosed
• Treatment Options
• Living with an Immune System Disorder

What Is an Immune System Disorder?

An immune system disorder is a condition that occurs when your immune system doesn’t work the way it should. Your immune system is a complex network of cells, tissues, and organs that work together to defend your body against harmful invaders like bacteria, viruses, and other germs.^[1]

When your immune system is functioning normally, it can tell the difference between your own healthy cells and foreign substances that don’t belong in your body. However, when something goes wrong with this system, it can lead to various health problems.^[5]

How Your Immune System Works

Your immune system includes many different parts working together. The main components are white blood cells (special cells that attack and eliminate harmful germs), antibodies (proteins that protect you from invaders), and various organs including the spleen, thymus, tonsils, lymph nodes, and bone marrow.^[1]

When germs such as bacteria or viruses invade your body, they attack and multiply, causing an infection. Your immune system responds by recognizing these harmful substances, called antigens, and attacking them. This response includes making antibodies that work to attack, weaken, and destroy the invaders. Your body also remembers the antigen, so if it sees it again, it can quickly send out the right antibodies to protect you.^[1]

The immune system has two main parts. The innate immune system is your first line of defense that you’re born with, including barriers like your skin and mucous membranes. The adaptive immune system develops over time as you’re exposed to different germs, creating lasting protection against many diseases.^[9]

Types of Immune System Disorders

There are several main categories of immune system disorders, depending on what goes wrong with your immune system.^[5]

You may be born with a weak immune system, which is called primary immune deficiency. Alternatively, you can develop a disease that weakens your immune system, known as acquired immune deficiency. Your immune system might also be too active, which can happen with allergic reactions. Finally, your immune system might turn against you and attack your own body, which is called autoimmune disease.^[3]

Autoimmune Diseases

Autoimmune diseases happen when your immune system attacks your body instead of defending it. Usually, your immune system is like your body’s built-in security system, automatically detecting substances that shouldn’t be in your body and sending out white blood cells to eliminate them. But if you have an autoimmune disease, your immune system is more active than it should be and, because there aren’t invaders to attack, it turns on your body and damages healthy tissue.^[2]

There are more than 100 different autoimmune diseases. They can affect almost any tissue or organ in your body, depending on where your immune system malfunctions. Autoimmune diseases are common, with experts estimating that around 1 in 15 people in the U.S. has an autoimmune disease.^[2]

Some examples of autoimmune diseases include:

• Rheumatoid arthritis, which affects joints and causes inflammation, swelling, and pain
• Lupus (systemic lupus erythematosus), which can attack joints, lungs, blood cells, nerves, and kidneys
• Type 1 diabetes, where antibodies attack and destroy insulin-producing cells in the pancreas
• Multiple sclerosis, which attacks nerve cells and can cause pain, blindness, weakness, and muscle spasms
• Inflammatory bowel disease, including Crohn’s disease and ulcerative colitis, which attacks the lining of the intestines
• Psoriasis, which affects the skin and causes silvery, scaly patches
• Hashimoto’s thyroiditis and Graves’ disease, which affect the thyroid gland

Autoimmune diseases are chronic conditions, meaning if you have an autoimmune disease, you’ll probably have to manage it and the symptoms it causes for the rest of your life.^[2]

Immunodeficiency Disorders

Immunodeficiency disorders occur when your immune system doesn’t work correctly, making you get sick more often. Your infections may last longer and can be more serious and harder to treat.^[1]

Primary immunodeficiency disorders are conditions you’re born with. One example is severe combined immunodeficiency (SCID), sometimes called “bubble boy disease.” Children with SCID are missing important white blood cells and are in constant danger of infections from bacteria, viruses, and fungi. This disease is deadly without treatment.^[3]

Acquired immune deficiencies develop later in life. Your immune system can be weakened by certain medicines, such as chemotherapy drugs used to treat cancer or medicines taken after organ transplants to prevent rejection. Infections like the flu virus, mono (mononucleosis), and measles can also weaken your immune system temporarily. Additionally, smoking, alcohol, and poor nutrition can weaken your immune system.^[5]

HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems and get an increasing number of severe illnesses.^[1]

Overactive Immune System

Sometimes your immune system can react too strongly to invaders, whether real or perceived. It may mount an attack when there’s no actual invader, or it may keep attacking after getting rid of an invader. An overactive immune system can lead to problems like autoimmune diseases or allergic reactions.^[6]

If you are born with certain genes, your immune system may react to substances in the environment that are normally harmless. These substances are called allergens. Having an allergic reaction is the most common example of an overactive immune system.^[5]

Some conditions caused by an overactive immune system include:

• Asthma, where the response in your lungs can cause coughing, wheezing, and trouble breathing
• Eczema (atopic dermatitis), where an allergen causes an itchy rash
• Hay fever (allergic rhinitis), causing sneezing, a runny nose, and swelling of nasal passages from allergens like dust, pets, or pollen
• Food allergies, which can cause severe allergic reactions

What Causes Immune System Disorders?

Experts don’t know for certain what causes autoimmune diseases and many immune system disorders. For autoimmune diseases, we know your immune system mistakenly damages your body instead of protecting it, but the exact triggers remain unclear.^[7]

Normal healthy individuals have circulating immune cells that are capable of attacking their own tissues, but most people don’t develop autoimmune disease. In healthy individuals, the potential harm from these self-reactive cells is counterbalanced by regulatory mechanisms that constantly work to suppress potentially damaging responses, maintaining tolerance to self.^[11]

Many immunodeficiency disorders are genetic, meaning they are inherited and present from birth. Others develop due to infections, medications, or other factors that weaken the immune system over time.^[1]

For unknown reasons, women are more susceptible to autoimmune diseases than men, particularly during their childbearing years. It is thought that sex hormones may be at least partly responsible.^[10]

Common Symptoms

Immune system disorders can cause a wide range of symptoms depending on which type of disorder you have and which parts of your body are affected.^[2]

For autoimmune diseases, symptoms can affect your body from head to toe. Many autoimmune diseases cause inflammation, which can include a feeling of warmth or heat, discoloration or redness on your skin, swelling, and pain. Conditions that affect your muscles can cause muscle weakness. You might have joint pain, swelling, or stiffness. Some autoimmune conditions affect your vision or cause changes in blood sugar levels.^[2]

Many autoimmune diseases cause symptoms that come and go. These episodes of more noticeable or more severe symptoms are called flares or attacks.^[2]

For immunodeficiency disorders, the main sign is getting sick more often than other people. You may have infections that last longer, are more serious, and are harder to treat than infections in people with normal immune systems.^[1]

Nobody knows what’s normal for your body better than you. You should visit a healthcare provider if you notice any new symptoms you can’t explain, especially if you don’t feel like yourself more often than usual.^[2]

How Disorders Are Diagnosed

To diagnose an immune system disorder, a healthcare professional will ask about your history of illnesses and whether any close relatives have an inherited immune system disorder. A physical examination will also be done.^[8]

Blood tests are commonly used to diagnose immune disorders. These tests can determine if you have typical levels of infection-fighting proteins, called immunoglobulins, in your blood. Blood tests also measure the levels of blood cells and immune system cells. Having numbers of certain cells that are outside of the standard range can indicate an immune system defect. Blood tests can also tell if your immune system is responding properly by checking whether it produces antibodies that find and kill foreign invaders.^[8]

Diagnosis can take several years, especially when symptoms are not taken seriously or when the patient is made to feel by friends or family that the symptoms are all “in one’s head.” This can contribute to patients feeling uncertain about their own symptoms and questioning their knowledge about their own bodies. During this lengthy process, the disease continues to cause damage.^[19]

Treatment Options

There is generally no cure for most immune system disorders, but the symptoms can be managed. Treatment depends on the specific type of disorder you have.^[2]

For autoimmune diseases, treatments focus on reducing immune system activity. Many different medications can suppress your immune system to prevent it from attacking your body. Some medicines are taken by mouth, while others are given as shots. Common treatments include steroids like prednisone, which reduce immune system function, and various other immune-suppressing medicines.^[2]

Recent advances in treatment include costimulation blockade, regulatory T cell therapy, antigen-specific immunotherapy, and manipulating certain immune pathways. These newer approaches attempt to restore the balance between attacking harmful invaders and protecting your own tissues.^[11]

For immunodeficiency disorders, treatments include preventing and treating infections with antibiotics, which may require longer courses than usual. Some people need immune-boosting treatments. Immunoglobulin replacement therapy can provide antibodies to help fight infections. In severe cases, procedures like hematopoietic stem cell transplantation or gene therapy may be options.^[8]

It’s important to work closely with your healthcare provider to find treatments that manage the symptoms you experience, as each person’s condition and response to treatment can be different.^[2]

Living with an Immune System Disorder

Living with an immune system disorder requires a proactive approach to health. Taking care of yourself doesn’t have to be complicated, but commitment and consistency are necessary for success.^[15]

Following general good-health guidelines is the single best step you can take toward keeping your immune system working as well as possible. This includes not smoking, eating a diet high in fruits and vegetables, exercising regularly, maintaining a healthy weight, drinking alcohol only in moderation, getting adequate sleep, and taking steps to avoid infection by washing your hands frequently.^[17]

If you have a weakened immune system, basic hygiene is especially important. Wash your hands for 20 seconds with soap and water at mealtime and when contact is made with other people. Use hand sanitizer and bacterial wipes in between. Avoid touching your eyes, nose, and mouth. Shower and bathe regularly, and keep up with dentist visits.^[15]

To further prevent exposure to infections, consider wearing a mask in large gatherings, physically distance yourself from others when needed, and avoid being in enclosed spaces without good ventilation for prolonged periods. Avoid being in contact with individuals who may be feeling ill.^[15]

Stay up to date on vaccinations recommended by your healthcare team. Vaccines can provide additional protection against preventable diseases and help strengthen your immune response. This is very important for individuals who have been treated with certain medications. Some vaccines may need to be timed in accordance with your medication schedule, so seek the input of your healthcare team.^[14]

Managing stress is also important. There has been an association between high levels of chronic stress and the ineffectiveness of the immune system. Incorporate stress-reducing activities such as meditation, deep breathing, yoga, or enjoyable hobbies into your routine. Exercise has been proven to reduce stress levels and boost immune system function. It is recommended to do at least 3-5 days of 30 minutes of aerobic exercise per week.^[14]

A common theme that emerges among people living with immune system disorders is the feeling of being alone with their illness. Many find that family and friends are available and supportive initially or during a crisis, but that support fades over the long run. Remember that friends and family have also experienced the loss of your former self and may become anxious or depressed themselves.^[19]

Being diagnosed and living with an immune system disorder affects your self-image and how you experience yourself. Feelings of low self-esteem, sadness, and even depression are commonly experienced, and some people may find support groups or psychotherapy helpful.^[19]

With the right support, resources, and self-care strategies, many people with immune system disorders lead full and active lives.^[15]