Your immune system is a fascinating, interconnected network. It protects you from millions of harmful bacteria, microbes, viruses, toxins and parasites, yet most people often don’t give it a second thought.
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At the break of skin and the openings of your mouth and nose, it is the border patrol. If invaders do get inside your body, it sends out lines of defense, whether in the blood, organs, muscles or bones.
This internal police force is vital to life, though sometimes it does get overzealous. When this happens, the immune system can work against us, causing allergic reactions or at its worst, autoimmune disorders, such as lupus and multiple sclerosis.
At other times, it weakens, fails and becomes ineffective.
Why does this happen? What turns the volume of your immune system up or down?
Rheumatologist Leonard Calabrese, DO, answers common questions about what happens when your immune system falters.
Q: What happens when your immune system fails?
A: Think of how many times you come into contact with someone who has a cold or the flu. Imagine how often your immune system fights off those germs and keeps you in the pink. But what if, instead, every one of those illnesses gained a foothold in your body? You might go from one illness to another, without ever recovering in between.
When the failure is severe, you will see more complications from those illnesses and infections, and you’ll recover much more slowly. Instead of bouncing back within days or a week, you could suffer for several weeks or months.
When your immune system fails completely, you’re left without any natural protection against illness. This leaves you open to “opportunistic infections” — sicknesses that can even come from things that ordinarily wouldn’t harm you. These can include recurrent pneumonia, herpes simplex and tuberculosis among other infections.
People who are immunocompromised, such as those with HIV, fall into this last group. This makes certain types of cancer, such as lymphoma, more likely.
Q: What happens with an overactive immune system?
A: In many cases, an immune system that overreacts is as harmful and dangerous as one that stops working.
In general, an overactive immune system leads to many autoimmune disorders — because of hyperactive immune responses your body can’t tell the difference between your healthy, normal cells and invaders. In essence, your immune system turns against you.
Q: What conditions can arise from an overactive immune system?
A: Common conditions caused by an overactive immune system include:
- Rheumatoid arthritis: Your immune system attacks your joints, leading to inflammation, redness, pain and stiffness. Over time, your joints can become deformed and you can lose function.
- Multiple sclerosis: Your immune system destroys the fatty layer that surrounds and protects your nerves from damage. Without it, you’re vulnerable. As this disease progresses, it attacks your brain, spine and eyes, causing problems with your balance, muscle control, vision and other bodily functions.
- Celiac disease: With this condition, when you eat gluten your immune system attacks the small intestines, damaging the finger-like projections (called villi) that help your body absorb nutrients.
Other autoimmune conditions include:
- Lupus (affects skin, joints and blood cells)
- Vasculitis (affects blood vessels)
- Sjögren’s syndrome (causes dry eyes and dry mouth)
- Inflammatory bowel syndrome (affects the digestive tract)
- Chronic fatigue syndrome (causes sleep abnormalities and pain)
Q: What causes immune system failure?
A: Doctors still don’t know exactly why the immune system sometimes fails. But, there are clues to how it happens. The immune system is an integrated network that’s hard-wired into your central nervous system, Dr. Calabrese says. So, when it’s healthy, everything works automatically.
But, things go haywire when the system starts to crumble. For example, if you don’t sleep well and get stressed out, your body will produce more of the stress hormone cortisol.
Over time, high cortisol levels can have a degenerative effect on your body. Healthy bone and muscle break down and slow the healing process. Cortisol can interfere with digestion and metabolism, as well as adversely affecting your mental functions.
Q: How can you help your immune system?
A: Though we don’t always know exactly why an immune system fails, we do know that adopting healthy habits can help keep your immune system ticking along well and always ready for defensive action, Dr. Calabrese says.
A healthy diet, regular exercise, getting enough sleep and managing stress all can help. These steps help support good cardiovascular health, which, in turn, contributes to a healthy immune system.