Immunodeficiency disorders prevent your body from fighting infections and diseases as well as it should. This type of disorder can make it easier for you to develop viral or bacterial infections.

Key points

  1. Immunodeficiency disorders affect your body’s ability to defend itself against bacteria, viruses, and parasites.
  2. There are two types of immunodeficiency disorders: those you are born with (primary) and those that are acquired (secondary).
  3. Anything that weakens your immune system may lead to a secondary immunodeficiency disorder.

Immunodeficiency disorders are either congenital or acquired. A congenital, or primary, disorder is one you were born with. An acquired, or secondary, disorder is one you get later in life. Acquired disorders are more common than congenital disorders.

Your immune system includes the following organs:

These organs create and release lymphocytes, which are white blood cells classified as B cells and T cells.

B and T cells fight invaders by detecting specific parts of them known as “antigens.” B cells release antibodies specific to the antigen that your body detects. T cells can destroy foreign or atypical cells.

Your B and T cells might need to fight off:

  • bacteria
  • viruses
  • cancer cells
  • parasites

An immunodeficiency disorder disrupts your body’s ability to defend itself against these.

What is a weak immune system?

If you have a “weaker” immune system, it means your body is immunocompromised. This means your body can’t fight off infections or viruses as well as people who are not immunocompromised.

While a weaker immune system is typically caused by certain diseases, malnutrition, and certain genetic disorders, it may also be temporary, as a result of medications such as anticancer drugs and radiation therapy.

Your immune system can also be temporarily weakened by a stem cell or organ transplant.

There are hundreds of types of immunodeficiency disorders. Each disorder has unique symptoms that can be frequent or chronic. However, there are a few warning signs that something may be going on with your immune system.

Individuals with immunodeficiency disorders tend to have frequent infections — one round after another — of certain conditions, such as:

Individuals with immunodeficiency disorders may also develop chronic abdominal pain, and they may even lose weight over time.

If you find that you get sick easily and have a hard time shaking off viruses and other infections, your doctor might suggest you get tested for an immunodeficiency disorder.

An immune deficiency disease or disorder occurs when the immune system is not working as expected. If you’re born with a deficiency from a genetic cause, it’s called primary immunodeficiency disease. There are more than 200 primary immunodeficiency disorders.

Examples of primary immunodeficiency disorders include:

  • common variable immunodeficiency (CVID)
  • severe combined immunodeficiency (SCID), which is also known as alymphocytosis
  • chronic granulomatous disease (CGD)

Secondary immunodeficiency disorders happen when an outside source, like a chemical or infection, weakens your body. The following can cause a secondary immunodeficiency disorder:

Examples of secondary immunodeficiency disorders include:

Primary immunodeficiency disorders are most commonly caused by inherited gene mutations.

People who have a family history of primary immunodeficiency disorders have a higher risk of developing primary disorders themselves.

Secondary immunodeficiency disorders can be caused by a variety of things, including:

  • chronic conditions (like diabetes or cancer)
  • drugs
  • radiation therapy (this is rare)
  • long-term hospitalization
  • insufficient nutrition

Anything that weakens your immune system can lead to a secondary immunodeficiency disorder. For example, exposure to body fluids containing HIV or organ removal and replacement can both be causes.

Aging can also weaken your immune system. As you age, some of the organs that produce or process white blood cells shrink and become less efficient.

Proteins are important for your immunity. Not getting enough protein in your diet can weaken your immune system.

Your body also produces proteins when you sleep that help your body fight infection. For this reason, lack of sleep can reduce your immune defenses.

Cancers and chemotherapy drugs can also reduce your immunity.

If your doctor thinks you might have an immunodeficiency disorder, they may:

Your doctor may also perform a skin test, which is usually done when a T-cell abnormality is suspected.

During a skin test, a small number of proteins from common infectious organisms (like yeast) are injected right under the skin. If there’s no reaction (such as swelling or redness) within 2 days, that can be a sign of an immunodeficiency disorder from a T-cell abnormality.

Biopsies of the lymph nodes or bone marrow may also be performed to help your doctor narrow down which disorder may be causing your symptoms.

A doctor may also recommend genetic testing, usually via a blood test, to determine if there are any gene mutations that may be causing your immunodeficiency disorder.

Treating immunodeficiency disorders typically involves:

  • preventing infections when possible
  • treating infections when they occur
  • strengthening parts of your immune system

Antibiotics and immunoglobulin therapy are two types of medications often used in treatment.

Other antiviral drugs, like oseltamivir, acyclovir, or interferon, are sometimes used to treat viral infections caused by immunodeficiency disorders.

If your bone marrow isn’t producing enough lymphocytes, your doctor might suggest a bone marrow (stem cell) transplant.

Primary immunodeficiency disorders can be managed and treated, but they can’t be prevented.

The risk of developing secondary disorders can sometimes be lowered through lifestyle choices. For example, it’s possible to lower your risk of developing type 2 diabetes by eating a nutritious diet and getting enough physical activity.

Sleep is very important for a healthy immune system. According to the CDC, long-term sleep loss may lead to a variety of chronic conditions and weaken the body’s ability to fight infections.

If your primary care physician has diagnosed you with an immunodeficiency disorder or suspects you might have one and wants an expert opinion, they will most likely send you to an immunologist.

Immunologists specialize in immunodeficiency disorders. Typically, after gaining a bachelor’s degree, individuals who want to become immunologists must go through 9 years of additional medical training.

To be board certified, they must pass an exam by the American Board of Allergy and Immunology (ABAI).

If you’ve been diagnosed with an immunodeficiency disorder, it means that your immune system is not able to fight off infections or viruses effectively. You may have been born with it, or it could have arisen later in life due to a chronic condition, such as diabetes or cancer.

There are hundreds of forms of immunodeficiency disorders. Around 6 million people worldwide live with a primary immunodeficiency disorder (the type you are born with).

Most doctors agree that people with immunodeficiency disorders can lead full and productive lives. Early identification and treatment of the disorder are very important.

Q:

I have a family history of immunodeficiency disorders. If I have children, how early should they be screened for it?

Anonymous person

A:

A family history of primary immunodeficiency is the strongest predictor of a disorder. At birth and for only a few months, babies are partially protected from infections by antibodies transmitted to them by their mothers.

Typically, the earlier any signs of an immunodeficiency show up in children, the more severe the disorder. Testing can be done within the first few months, but it’s also important to recognize the early signs: recurrent infections and failure to thrive.

Initial laboratory screening should include a complete blood count with differential and measurement of serum immunoglobulin and complement levels.

Brenda B. Spriggs, MD, FACPAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.