Molecular Mimicry—An Autoimmune Theory
Molecular mimicry is the theory that bacterial cells or other microbial “triggers” have a similar appearance to the cells that make up parts of our physiology or “self” antigens.
When an infection occurs, these infectious cells are recognized as foreign. This is really great for getting rid of the infections, but sometimes the immune system targets proteins in the infectious cells that resemble the proteins in our own cells. This inadvertently causes a cross-reaction with our “self” antigens, i.e., our own cells. This case of mistaken identity is thought to trigger the start of autoimmunity.
One example is Streptococcus pyogenes. This is the bacteria that causes the common throat infection known as “strep throat.” In some cases, especially when the infection is not treated with antibiotics within two to three weeks, the immune system will start launching an attack against the Streptococcus bacteria.
Unfortunately, a component of the bacteria’s cell wall resembles that of the human heart valves, and this results in the immune system attacking the human heart valves in a case of mistaken identity. This reaction is known as rheumatic fever and can be deadly, and often necessitates heart valve transplants. Arnold Schwarzenegger is probably the most well-known person who was affected with this condition and has had to have heart valve transplants as a result.
Which Bacteria Have Been Associated with Triggering Hashimoto’s?
A variety of bacterial infections have been implicated in triggering autoimmune thyroiditis, including Helicobacter pylori (the same bacteria that causes ulcers), Borrelia burgdorferi (associated with Lyme disease), and Yersinia enterocolitica.
Antibodies to Yersinia (indicating exposure) in people with Hashimoto’s were found fourteen times more often than in people without Hashimoto’s. Yersinia membranes contain a site that binds TSH, making it a prime suspect based on the molecular mimicry theory. Infection with this bacteria can induce antibodies against sites that recognize and stimulate TSH receptors, like the thyroid peroxidase enzyme or thyroglobulin.
People can contract a Yersinia enterocolitica infection from contaminated meat, poultry, dairy products, and seafood (especially oysters). In 2012, a consumer group found that 67 percent of pork sold in the U.S. was contaminated with Yersinia!
Physicians can run blood tests, stool antigen or breath tests for H. pylori. If you cannot find a physician that will run the test for you, you can also order your own labs tests via direct-to-patient lab testing that I have set up through Direct Labs. You can find a practitioner near you who believes in the root cause approach by downloading my free guide here.
Borrelia detection is available as a blood test, while the presence of Yersinia can be tested by a comprehensive stool analysis. You will need to request Yersinia to be added to the test panel.
New autoimmune theories have established that once the antigen (trigger) is removed, the antibody production goes away and the innocent part of our bodies (in the case of Hashimoto’s, the TPO enzyme) is no longer a target.
In the case of infections, once the infection is removed, the TPO enzyme should no longer be a trigger once the immune system recognizes that the infection is gone. Thus, treating infections may help to heal Hashimoto’s. In other cases, the infection may be gone and the immune system may need a reboot.
Antibiotics for Autoimmune Conditions?
Some individuals have reported the normalization of thyroid peroxidase antibodies following taking the antibiotic doxycycline, which is effective for Yersinia enterocolitica and Borellia burgdorferi, as well as other bacteria.
Work with your doctor to test for infections, and use antibiotics judiciously, as they can be incredibly dangerous when used incorrectly and lead to multi-drug resistance, an elimination of the beneficial bacterial flora and numerous side effects. There are a multitude of different antibiotics, each with a different group of bacteria they target, and each with their own set of side effects. Blindly taking antibiotics without knowing the cause of your infection may end up inadvertently destroying the beneficial bacteria while letting pathogenic and opportunistic bacteria thrive.
Be sure to supplement with probiotics during courses of antibiotic therapy, but at different times throughout the day, so that the beneficial bacteria in the probiotics are not killed by the antibiotics. Work with your pharmacist to find out the half-life of your antibiotics and to find an optimal time to take probiotics.
Treatments for H. Pylori
H. pylori is a stubborn infection. Standard medical treatments for H. pylori include:
- Triple therapy: Two antibiotics: Amoxicillin or metronidazole plus clarithromycin, with a proton pump inhibitor (While proton pump inhibitors can make us more susceptible to H. pylori by themselves, they work in synergy with antibiotics to reduce H. pylori.)
- Quadruple therapy: Pepto Bismol + tetracycline + metronidazole + proton pump inhibitor
Some individuals may be hesitant to try antibiotics. Integrative clinicians have reported much success with using natural remedies like the ones listed below:
- Probiotics and fermented foods like lacto-fermented sauerkraut
- Extra-virgin coconut oil
- Whole cloves of garlic
- Fermented foods
- Glycyrrhizin (licorice)
- N-acetyl cysteine
- Coenzyme Q10
- Oil of oregano
- Aloe vera juice
- Mastic gum
Note: Not everyone will test positive for one of these infections; not everyone will be helped by doxycycline or the natural substances I listed. These are just a few of the things that could be at the root cause of Hashimoto’s… There are many other triggers…
If there is a pressing issue for you, send me a message or leave a comment. I am here to help.
If you are new here, here are some other posts you may be interested in:
- Reversing Autoimmunity
- What’s Really Going On in Hashimoto’s
- Is It Possible to Recover Thyroid Function in Hashimoto’s
NOTE: These statements have not been evaluated by the Food and Drug Administration. The products discussed are not intended to diagnose, treat, cure, or prevent any disease.
The medical information on this blog is provided as an educational resource only and is not intended to be used or relied upon for any diagnostic or treatment purposes. This information should not be used as a substitute for professional diagnosis and treatment.
Please consult your health-care provider before making any healthcare decisions or for guidance about a specific medical condition.
PS. You can also download a free Thyroid Diet Guide, 10 thyroid-friendly recipes, and the Nutrient Depletions and Digestion chapter of my first book for free by signing up for my weekly newsletter. You will also receive occasional updates about new research, resources, giveaways and helpful information.
- Rojas M, Restrepo-Jiménez P, Monsalve DM, et al. Molecular mimicry and autoimmunity. J Autoimmun. 2018;95:100-123. doi:10.1016/j.jaut.2018.10.012
- Guilherme L, Faé KC, Oshiro SE, Tanaka AC, Pomerantzeff PM, Kalil J. Rheumatic fever: how S. pyogenes-primed peripheral T cells trigger heart valve lesions. Ann N Y Acad Sci. 2005;1051:132-140. doi:10.1196/annals.1361.054
- Figura N, Di Cairano G, Moretti E, et al. Helicobacter pylori Infection and Autoimmune Thyroid Diseases: The Role of Virulent Strains. Antibiotics (Basel). 2019;9(1):12. Published 2019 Dec 30. doi:10.3390/antibiotics9010012
- Benvenga S, Santarpia L, Trimarchi F, Guarneri F. Human thyroid autoantigens and proteins of Yersinia and Borrelia share amino acid sequence homology that includes binding motifs to HLA-DR molecules and T-cell receptor. Thyroid. 2006;16(3):225-236. doi:10.1089/thy.2006.16.225
- Vojdani A. A Potential Link between Environmental Triggers and Autoimmunity. Autoimmune Dis. 2014;2014:437231. doi:10.1155/2014/437231
Note: Originally published in February 2015, this article has been revised and updated for accuracy and thoroughness.