Viruses and bacteria that thrive in our bodies are everywhere. Luckily, we have a strong defense to attack and destroy these foreign invaders: our immune system. Without it, we would be defenseless against germs, become ill and die.
Occasionally, genetic anomalies result in infants born with defective immune systems. An extreme case was the so-called “bubble boy,” who lived 12 years in a protected, germ-free environment at a Texas hospital after being born in 1971 with severe combined immune deficiency. Newborns are routinely tested for some of these genetic disorders, but congenital immunodeficiencies can be diagnosed at any age.
Much more common are secondary immunodeficiencies, which occur when a once healthy immune system is weakened by external factors like cancer or autoimmune conditions. In many cases, when the cause is removed or treated, the immune system returns to normal. However, in some cases, patients are left with residual immunodeficiencies.
What Is the Immune System?
The immune system consists of two main parts: The general immune system and the specialized immune system.
The general (also called innate) immune system is made up of these progressive lines of defense:
- The skin presents a physical barrier that stops bacteria and viruses from entering the body and produces acid, enzymes and mucus to prevent them from growing.
- If these invaders enter the body through a break in the skin, certain proteins “tag” viruses and bacteria to identify them as intruders.
- Scavenger cells called phagocytes seek out, swallow and digest tagged germs and viruses.
- Natural killer cells search the body for malignancies – tumor cells, for example — and destroy them.
The specialized immune system (also called adaptive) consists of single-purpose cells called lymphocytes that “remember” invaders they’ve encountered before and go after them head-on. This is why you get some illnesses only once, and it’s the foundation for vaccinations that use non-infectious parts of certain dangerous germs to build immunity to them.
Signs of a Weakened Immune System
A healthy immune system can still become weakened due to infections (HIV, for example), certain medications (including corticosteroids), surgery or other traumas. The most common cause of immunodeficiency worldwide is malnutrition, affecting many communities around the world where access to food is restricted. Specifically, diets low in protein and certain micronutrients — including vitamin D — have been shown to alter immune responses.
These secondary immunodeficiencies announce themselves with symptoms including:
- Infections of the lungs, ears and skin recurring within a year
- Poor wound healing
- Easy bruising or bleeding
- Feeling tired frequently
- Bloating, constipation, gas, diarrhea
Secondary immunodeficiencies are treated by managing the primary condition: Curing the infection; recovering from surgery or other trauma; improving nutrition.
Diagnosing Immunodeficiency
If you or your healthcare provider suspects immunodeficiency, the initial workup will include routine blood work to check for appropriate levels of substances released by the immune system, including lymphocytes, white blood cells, immunoglobulin and protein. Additionally, your healthcare provider may:
- Order specific tests to check for viruses in your system
- Order a skin test to determine your body’s reaction to a specific antigen — a substance that causes the body to produce an immune response
- Screen you for chronic infections and specific diseases.
The precise tests that are performed will depend on the type of infections that may be a problem.
Once a diagnosis is confirmed, your provider can begin treating the underlying cause of your immunodeficiency, whether by adjusting your diet, managing your chemotherapy, reducing dosage of certain medications, treating the infection or referring you to a specialist.
In many cases, removing the underlying cause will restore your immune system to normal, but in some cases — an HIV infection, for example — treatment with antiviral drugs, antifungals or antibiotics may be needed long term or even for the rest of your life.
Protecting Your Immune System
Those with a compromised immune system must make special efforts to protect themselves from infection. This can be done by avoiding crowded places, wearing a mask when crowds are unavoidable, getting vaccinated and washing hands frequently.
Other strategies that support a healthy immune system include the same lifestyle choices we hear about over and over again:
- Eating a balanced diet
- Getting regular aerobic exercise
- Getting adequate sleep
- Maintaining a healthy weight
- Avoiding alcohol, tobacco and other recreational drugs
- Minimizing stress
- Getting vaccines to prevent infections
In other words, a healthy lifestyle allows our bodies to do what they were designed to do, including protecting us from most germs.
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