Why Does the Body Attack Itself?

Lesson Plan - Get It!

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The Immune System’s Job: Friend or Foe?

Your immune system is designed to protect you from outside threats, such as bacteria, viruses, parasites, and toxins. 

• Dendritic cells detect invaders.

• T cells sound the alarm or fight directly.

• B cells produce antibodies.

• Phagocytes gobble up the invaders.

These specialized cells work together like a well-trained army, identifying enemies (called antigens) and attacking them before they can make you sick .

• But what happens when the immune system mistakes healthy cells—your own cells—for antigens?

Autoimmunity: Friendly Fire

When your immune system can't tell the difference between harmful invaders and your own body, it attacks healthy tissues. This is called an autoimmune response.

• And the result?

Pain, inflammation, and sometimes long-term damage. Instead of saving the day, the immune system becomes the problem.

Scientists still don’t fully understand why this happens, but several triggers are known to play a role.

• Genetics (family history)

• Viruses or infections

• Environmental pollutants

• Certain foods (like gluten in celiac disease)

• Medications

• Hormonal changes or imbalances

• Stress

Examples You Might Know

Autoimmune diseases can affect nearly every part of the body. Here are just a few common ones.

There are over 100 different autoimmune diseases, and new ones are still being studied.

Diagnosing the Problem

Autoimmune diseases can be tricky to identify because their symptoms often look like other illnesses. Doctors use a variety of diagnostic tools.

• Blood tests (for autoantibodies and inflammation markers)

• Imaging (like MRIs or ultrasounds to detect tissue damage)

• Symptom tracking and medical history

Diagnosis can take months or even years, especially if symptoms come and go.

Can Autoimmunity Be Treated?

There’s no one-size-fits-all cure, but there are many treatment options. The goal is to calm the overactive immune system without completely shutting it down.

Here are some common treatments.

• Steroids (to reduce inflammation fast)

• Immunosuppressants (to slow down the immune attack)

• Biologics (target specific parts of the immune system)

• Pain relievers and anti-inflammatories

• Hormone therapy (like insulin or thyroid hormones)

• Plasma exchange (filters harmful antibodies from the blood)

• Stem cell therapy (experimental but promising)

Doctors may also recommend lifestyle changes, such as stress reduction, healthy eating, avoiding smoking, or regular exercise, to help manage symptoms.

Living With Autoimmunity

People with autoimmune conditions often face various challenges.

• Daily pain or fatigue

• Emotional stress

• Food or activity limitations

• The challenge of “invisible” symptoms others don’t understand

But there’s hope. Medical research is advancing, and better treatments are being developed every year.

Many people with autoimmune diseases live full, active lives—especially when their condition is diagnosed early and managed well

What Happens Next?

Autoimmunity can sound overwhelming, but now you’ve got the tools to understand it! You know how the immune system works, what happens when it malfunctions, and what that means in real life.

Head to the Got It? section to review what you’ve learned with fun practice activities and quizzes to sharpen your thinking.

Let’s keep learning!