The immune system is a complex set of organs, cells, proteins and other substances that function to prevent infection. Autoimmunity is one form of immune dysregulation in which the immune response is directed against normal parts of the body such as cells, tissues or organs. When your body is trying to fight an infection, allergen, a toxin or food, your thyroid, joints, brains, gut or even the whole body may become the victim!
According to the American Autoimmune Related Diseases Association (AARDA), 50 million Americans — 20 percent of the population — suffer from autoimmune diseases. Autoimmune diseases are more common in women during childbearing years. They frequently appear in women who have just had a baby, after periods of high emotional or physical stress or accidents, with infections, during periods of hormonal change such as perimenopause, or after starting birth control pills or hormone replacement therapy. In the United States, the most common autoimmune diseases are thyroid diseases such as Hashimoto’s thyroiditis and Graves’ disease.
Infections and Autoimmune Diseases
There is more and more evidence of the role that chronic bacterial or viral infections play in the development of autoimmune disease. No one knows exactly how infections trigger autoimmune diseases, but because our immune systems are so complicated and each infection is unique, it’s likely that there are multiple factors involved.
Many autoimmune diseases are linked with alterations in the intestinal bacteria that trigger an autoimmune attack on whatever tissues are most susceptible. A recent study showed that in hyperthyroidism, there were obvious decreases in the beneficial bacteria Bifidobacterium and Lactobacillus, and increase of non-beneficial Enterococcus. There is also clinical evidence confirmed by studies that increased gut permeability is identified with autoimmune problems.
“Molecular mimicry” is one of the most common mechanism by which infections induce autoimmunity. That’s when the infection is so structurally similar to your thyroid tissues that your immune system goes to attack the infection and accidentally attacks your thyroid–this is basically a case of mistaken identity.
Direct bystander activation describes an indirect or non-specific activation of autoimmune cells caused by the inflammatory environment present during infection. An example of this is when virus-specific T cells migrate to the areas of a virus infection, where they release cytokines against virus infected cells, as well as against uninfected cells (“bystander killing”.)
Epstein-barr virus (EBV) is part of the herpes family and one of the most common viruses in humans. It also causes mononucleosis. Some studies have associated this condition with autoimmune thyroid conditions. It is believed that EBV may stimulate antibody-producing B lymphocytes, which are predisposed to make TSH receptor antibodies. This in turn may contribute to or exacerbate Graves’ Disease. A 2015 Polish study found the EBV in the thyroid cells of 80% of people with Hashimoto’s and 62.5% of people with Grave’s, while controls did not have EBV present in their thyroid cells.
The herpes simplex type 1 and type 2 viruses, causing oral and genital herpes have been studied most thoroughly in relation to autoimmunity. When they are active they might trigger an autoimmune response in your thyroid via the bystander activation effect.
Hepatitis C is a virus that attacks the liver and affects nearly three million Americans. Studies have shown that the prevalence of hepatitis C virus is slightly increased in patients with Hashimoto’s Thyroiditis and that chronic hepatitis C infection can be associated with thyroid autoimmunity.
Because the primary treatment for Hepatitis C is a type of interferon (an antiviral and immune regulator), this might also be an environmental trigger for autoimmune thyroid disease.
Yersinia enterocolitica is a bacterium that is typically transmitted via undercooked pork, contaminated water, meat, or milk and causes symptoms similar to food poisoning. By measuring Yersinia antibodies in thyroid patients, researchers have linked the bacteria to autoimmune thyroid disease. Due to the molecular mimicry phenomenon, your antibodies for Yersinia attack the thyroid as well.
Helicobacter pylori is bacteria that causes ulcers by attacking the stomach lining, allowing your stomach acid to seep in and eat away at your gut lining. In a study comparing H. pylori infection rates among groups of autoimmune and thyroid patients, 86% of autoimmune thyroid patients tested positive for H. pylori, compared to 40% of non-autoimmune thyroid patients, and 45% of non-thyroid autoimmune patients.
If you were diagnosed with an autoimmune disease or you suspect having one of these infections, you should get tested. This is important because chronic infections can hinder the ability of your body to heal and can also trigger more complications.