If you live with an autoimmune condition, you may have asked yourself:

Why did this happen?
Why won’t my body calm down?
Why do my symptoms flare even when I’m “doing everything right”?

If you read my last blog on viruses and autoimmune diseases, you know that the primary explanation for autoimmune disease has been genetics. And while genetics do matter, they are only part of the story.

Research over the last decade has increasingly pointed toward another major piece of the puzzle:

Bacteria— and how they interact with your immune system.

Let’s break this down in a way that actually makes sense.

Your Immune System and Bacteria: A Lifelong Relationship

Your body is not sterile. In fact, you are home to trillions of bacteria, especially in your gut, mouth, skin, and mucosal surfaces.

Many of these bacteria are beneficial. They:

• Help digest food
• Produce vitamins
• Train your immune system
• Protect against harmful microbes

This balanced ecosystem is called your microbiome.

When this system is healthy, your immune system learns tolerance, meaning it knows what to attack and what to leave alone.

But when this balance is disrupted, problems can begin.

When Bacteria Become a Trigger

Certain bacterial infections have been strongly associated with autoimmune diseases.

Some examples include:

• Group A Streptococcus (strep throat) linked to rheumatic fever and PANDAS/PANS
• Helicobacter pylori linked to Hashimoto’s thyroiditis and autoimmune gastritis
• Porphyromonas gingivalis (a gum infection bacterium) associated with rheumatoid arthritis
• Yersinia enterocolitica studied in thyroid autoimmunity
• Borrelia burgdorferi (Lyme disease) associated with post-infectious autoimmune patterns
• Campylobacter and Salmonella linked to reactive arthritis

This does not mean bacteria always cause autoimmune disease, but it does mean infections can act as triggers, especially in genetically susceptible individuals.

It’s Often Not Just One Infection

One important concept from research is this: It may not be a single infection that causes autoimmune disease.

Instead, it may be the lifetime burden of infections that gradually shifts immune balance.

Think of it like cumulative stress on the immune system:

• Childhood infections
• Recurrent strep
• Gut infections
• Food poisoning
• Chronic sinus infections
• Lyme disease
• Untreated dental infections

Over time, the immune system can become dysregulated.

How Bacteria Trigger Autoimmunity

There are several mechanisms scientists have identified.

1. Molecular Mimicry

Some bacteria resemble human tissues.
When the immune system attacks the bacteria, it may accidentally attack similar-looking tissue in the body.

This has been observed in:

• Rheumatic fever after strep
• Certain thyroid conditions
• Rheumatoid arthritis

2. Superantigens: Immune Overactivation

Certain bacteria release toxins called superantigens.

Unlike normal immune triggers that activate a small number of immune cells, superantigens can activate up to 30% of T-cells at once.

This massive activation can:

• Break immune tolerance
• Trigger cytokine storms
• Activate previously silent self-reactive cells

This is one proposed mechanism in post-strep autoimmune syndromes and some inflammatory skin and neurologic conditions.

3. Gut Dysbiosis and Barrier Breakdown

Your gut lining is meant to act as a selective barrier.

When chronic infection, stress, antibiotics, or inflammation damage that lining:

• Bacterial fragments can enter circulation
• The immune system is repeatedly triggered
• Systemic inflammation increases

This is called dysbiosis and increased intestinal permeability.

It’s been strongly linked to:

• Inflammatory bowel disease
• Rheumatoid arthritis
• Multiple sclerosis
• Thyroid autoimmunity

In fact, research connecting the microbiome and autoimmunity has increased more than 300% in the last decade.

The Problem of Bacterial Persistence

Here’s something most patients are never told: Some bacteria are extremely good at hiding. They can:

• Live inside your cells
• Form protective biofilms
• Enter dormant “persister” states
• Transform into cell-wall-deficient forms
• Hide in tissues like tonsils, joints, or even the nervous system

This means symptoms may continue long after an “acute infection” was supposedly treated.

Antibiotics can reduce bacterial load.
But your immune system must ultimately clear the infection.

If immune balance is not restored, bacteria may persist, and inflammation may continue.

Biofilms: The Protective Shield

Many bacteria form biofilms (slimy protective communities) that shield them from:

• Antibiotics
• Immune attack
• Environmental stress

Biofilms can exist in:

• The gut
• The sinuses
• The tonsils
• Dental pockets
• Joints
• Implanted medical devices

These biofilms may contain bacterial amyloids (proteins that resemble human proteins). This molecular similarity may further confuse the immune system.

The Oral-Gut-Immune Connection

Oral bacteria deserve special attention. Porphyromonas gingivalis, a major periodontal pathogen, has been associated with rheumatoid arthritis and possibly multiple sclerosis.

It promotes:

• Th17 immune dominance
• Systemic inflammation
• Increased gut permeability
• Protein citrullination (a key feature in RA autoimmunity)

Can you believe that chronic gum disease is not just a dental issue?! It can be an immune issue. Sounds crazy, but science backs it up. 

Hashimoto’s and Bacterial Associations

One of the most studied bacterial associations in autoimmunity is Helicobacter pylori.

H. pylori infects over 50% of the global population.

It has been linked to:

• Hashimoto’s thyroiditis
• Autoimmune gastritis
• Vitamin B12 deficiency
• Iron deficiency
• Thrombocytopenia

Some studies have shown improvement in thyroid antibody levels after H. pylori eradication.

This does not mean everyone with Hashimoto’s has H. pylori.
But it does mean it may be worth evaluating in certain cases.

Why Antibiotics Alone Aren’t Enough

One of the most important takeaways from the research: antibiotics cannot completely eliminate infections on their own.

They reduce bacterial load. But without restoring immune competence, infections can regrow. This is why some people feel better temporarily… then relapse.

True healing requires:

• Supporting immune regulation
• Restoring barrier integrity
• Reducing inflammation
• Addressing biofilms and persistence
• Rebuilding resilience

A Functional Medicine Approach to Autoimmune Disease

Instead of asking only:

“What disease do you have?”

Functional medicine asks:

“What is your immune system reacting to?”

When I work with patients, we look at:

• Post-infectious onset patterns
• Cyclical flares
• History of recurrent infections
• Gut dysfunction
• Dental history
• Antibiotic history
• Environmental exposures
• Immune resilience

Testing may include:

• Microbiome analysis
• Barrier function markers
• Bacterial serology
• Inflammatory markers
• Immune profiling

But testing is only part of the picture.

The bigger goal is to help the immune system exit emergency mode.

4 Simple Ways to Start Supporting Healing at Home

While deeper investigation may be necessary, here are foundational steps anyone can begin:

1. Support Gut Integrity

• Prioritize whole, anti-inflammatory foods (check out these anti-inflammatory snacks)
• Increase fiber and polyphenol-rich vegetables
• Consider fermented foods if tolerated
• Remove known food triggers

2. Address Oral Health

• Daily flossing
• Professional dental cleanings
• Evaluate for chronic periodontal disease

3. Reduce Immune Burden

• Improve sleep consistency (aka doing your best to go to bed and wake around the same time)
• Manage stress physiology (choose a simple stress management tool to practice for even just 5 min a day)
• Address mold or environmental exposures
• Support detoxification pathways

4. Support Immune Regulation

• Adequate vitamin D
• Zinc and selenium (as appropriate)
• Omega-3 fatty acids
• Targeted probiotics (if indicated)

The goal is not to “boost” immunity. It’s to help it become balanced again.

Why Personalized Care Matters

Two people can have the same autoimmune diagnosis and completely different root drivers.

One may have:

• Persistent bacterial triggers

Another may have:

• Gut dysbiosis

Another may have:

• Viral reactivation

Another may have:

• Mold toxicity

Autoimmune disease is rarely one-size-fits-all.

That’s why cookie-cutter protocols often fail.

A Different Kind of Hope

If you’ve felt like your body is attacking you for no reason, I want you to hear this:

The immune system does not go to war without a reason.

Sometimes that reason is hidden.
Sometimes it’s layered.
Sometimes it’s been overlooked.

But it is worth investigating.

If you’re living with autoimmune symptoms and want to explore whether bacterial triggers, gut dysfunction, or immune dysregulation may be playing a role, I would be honored to walk through that with you. As a functional medicine registered nutritional therapist, I focus on identifying patterns, uncovering triggers, and building a plan that fits your story, not just your diagnosis.

If you’re ready to stop managing symptoms and start asking deeper questions, you can schedule a consultation with me, Linda, through this link (https://lindaverjus.com/schedule-with-linda/).

Let’s help your immune system move from survival mode to regulation. Healing begins when we look beneath the surface.

Sources:

Bacteria and autoimmune disease 2026. (2026). Unpublished presentation.

https://www.ifm.org/articles/role-of-microbiome-in-immune-diseases

Qiu, C. C., Caricchio, R., & Gallucci, S. (2019). Triggers of autoimmunity: The role of bacterial infections in the extracellular exposure of lupus nuclear autoantigens. Frontiers in Immunology, 10, Article 2608. https://doi.org/10.3389/fimmu.2019.02608