Which Viruses Can Trigger Thyroid Autoimmunity?
Published August 3 2015
There are numerous factors which can trigger an autoimmune thyroid condition such as Graves’ Disease or Hashimoto’s Thyroiditis, including certain types of viral infections. Although most viruses don’t directly trigger autoimmunity, in some cases they play a role in the initiation, progression, and perpetuation of autoimmune conditions (1). In this article I will discuss some of the more common viruses associated with thyroid autoimmunity. Then towards the end of the article I will discuss what someone can do to overcome such an infection.
I’d like to begin by talking about how a virus can lead to the development of an autoimmune condition. There can be a number of different mechanisms, including molecular mimicry, epitope spreading, and direct bystander activation (1). I’d like to go ahead and briefly discuss some of these different mechanisms. If you’re not interested in reading about these mechanisms you can skip ahead to the part where I discuss the different viruses associated with autoimmune conditions. And then towards the end of the article I’ll discuss how natural treatment methods can help combat viral infections.
Before talking about the mechanisms, I want to briefly explain what an antigen and antibody is for those who aren’t aware of what these are. An antigen is a substance that produces an immune response. So for example, foreign substances such as chemicals, bacteria, or viruses are considered to be antigens. Foods can also be perceived as antigens by the immune system. However, an antigen can also be produced inside of the body, and even the tissue cells can be considered to be an antigen at times, which is the case with autoimmune conditions such as Graves’ Disease and Hashimoto’s Thyroiditis. An antibody is a protein which is produced by the immune system, and this antibody binds to a specific antigen. Once the antibody binds to the antigen other immune system cells (i.e. macrophages) attempt to engulf and destroy the antigen.
Molecular mimicry. This is a process where a foreign antigen shares a sequence or structural similarities with self-antigens (2). So for example, a certain virus can have an amino acid sequence that is very similar to the amino acid sequence of human cells. This can result not only in the production of antibodies against the virus, but can also lead to autoantibodies against the human cells due to the similarities in the proteins.
Epitope spreading. This is when the immune response to an infection causes damage to the self-tissues. An epitope is part of an antigen that is recognized by the antibodies of the immune system, and is what the antibody specifically binds to. This is essentially a form of molecular mimicry. If there is a virus, normally the immune system will produce antibodies which attach to the epitope of the virus. With epitope spreading the antibodies will attach to the “self-epitopes”, which in turn will cause the immune system to attack the tissues of the body (3) (4).
Direct bystander activation. This describes an indirect or non-specific activation of autoimmune cells caused by the inflammatory environment present during infection. Think of this as a “domino effect”, as when one part of the immune system becomes activated this leads to the activation of other parts which can kill both viral-infected cells, and healthy cells as well. So for example, virus-specific T cells might migrate to the areas of a virus infection, and when these T cells encounter virus infected cells they release cytokines, which not only kill the infected cells, but also leads to “bystander killing” off the uninfected cells as well (5).
Hopefully you now have a better understanding of how a virus can trigger an autoimmune condition. Let’s go ahead take a look at some of the viruses which can trigger an autoimmune condition such as Graves’ Disease or Hashimoto’s Thyroiditis.
Epstein Barr. Epstein-barr virus (EBV) is one of the most common viruses in humans. EBV is usually spread through bodily fluids, primarily through the saliva (6). Although many people with EBV are asymptomatic, some of the symptoms associated with an EBV infection include fatigue, fever, sore throat, swollen lymph nodes in the neck, a rash, and an enlarged spleen (6).
Numerous studies have associated EBV with autoimmunity, including systemic lupus erythematosus (SLE), rheumatoid arthritis, and Sjögren’s syndrome (7). Some studies have also associated this condition with autoimmune thyroid conditions. For example, one study showed that EBV may stimulate antibody-producing B lymphocytes which are predisposed to make TSH receptor antibodies, which in turn may contribute to or exacerbate Graves’ Disease (8). Another small study showed that EBV antibodies are more common in those with autoimmune thyroiditis (9).
There is also evidence that EBV is linked to the development of various cancers, including nasopharyngeal carcinoma, gastric cancer, Burkitt lymphoma, non-Hodgkin lymphoma, and Hodgkin lymphoma (10). It is also possible that EBV can increase the progression of thyroid papillary carcinoma to undifferentiated carcinoma (11). Obviously I’m not suggesting that everyone with EBV will develop an autoimmune condition or cancer, but it does seem to lead to a higher incidence of these conditions.
Hepatitis C. Hepatitis C virus is the most common chronic bloodborne infection in the United States (12). Most people who become infected with this virus do so by sharing needles or other equipment to inject drugs, as well as the inadequate sterilization of medical equipment (13) (14). Although sometimes the infection can be mild in some people, in others it can lead to liver cirrhosis, or even liver cancer.
There does seem to be a relationship between hepatitis C and thyroid health. One study showed that the prevalence of hepatitis C virus is slightly increased in patients with Hashimoto’s Thyroiditis (15). This was confirmed in another study which showed that chronic hepatitis C infection can be associated with thyroid autoimmunity and hypothyroidism (16). Another study showed that hepatitis C had a higher incidence in those with Graves’ Disease, but not in patients with Hashimoto’s Thyroiditis (17). However, another study showed no significant association between chronic hepatitis C and thyroid autoimmunity, but it did show that interferon therapy for hepatitis C induced thyroid antibodies (18). I have written a separate article entitled “Is There a Connection Between Hepatitis C and Thyroid Health?“.
Parvovirus B19. Parvovirus B19 infects only humans, and the most common illness as a result of this virus is Fifth disease (19). This is a mild rash illness, and some of the initial symptoms include fever, runny nose, and headaches (20). It can also lead to rashes, along with painful or swollen joints. Parovirus B19 spreads through respiratory secretions such as saliva, sputum, or nasal mucus (20). One study showed strong evidence that acute parvovirus B19 infections are involved in the pathogenesis of some cases of Hashimoto’s Thyroiditis (21).
Herpes virus. Genital herpes is a sexually transmitted disease caused by two types of viruses. The viruses are herpes simplex type 1 and herpes simplex type 2 (22). This usually results in mild symptoms, and genital herpes sores usually appear as one or more blisters on or around the genitals, rectum, or mouth (22). However, it can also affect other areas such as the liver, lung, eye, and central nervous system (23). And there is evidence of a possible role of herpes simplex virus infections in the development of Hashimoto’s Thyroiditis (24). It also seems as if thyroid hormones regulate the gene expression of the herpes simplex virus, and thus may modulate the latency/reactivation of this virus (25).
HTLV-I. Human T-lymphotropic virus (HTLV-I) is estimated to infect 10 to 20 million people worldwide (26). One study showed a high prevalence of thyroid peroxidase and thyroglobulin antibodies in HTLV-1 carriers (27). Another study showed that there was a role of HLTV-1 in the development of both Hashimoto’s Thyroiditis and Graves’ Disease (28).
There are other viruses that can potentially trigger an autoimmune response and lead to a condition such as Graves’ Disease or Hashimoto’s Thyroiditis, but these are some of the more common viral infections seen in autoimmune thyroid conditions.
Can Natural Treatment Methods Help With Viruses?
There are nutrients and herbs which can help combat a viral infection. I will be listing some of the more important ones below, although keep in mind that this doesn’t mean that these nutrients and herbs will eradicate viruses. The reason why viruses are difficult to eradicate is because they infect our cells, and so the immune system usually has to kill the viral infected cell, and doesn’t just directly eradicate the virus. In most cases the goal will be to improve the health of the immune system and do things inhibit viral replication and to put the active viral infection into a dormant state, and hopefully keep it dormant for many years to come. Improving the health of the immune system is truly is the best method of both preventing and treating viral infections. So while taking certain nutritional supplements and herbs may help, one of course also needs to eat well, do a good job of managing their stress, get sufficient sleep, etc.
Vitamin D. I recommend for all of my patients to get tested for vitamin D. And while vitamin D is important for bone health, having healthy levels is important for optimal immune system health as well. And unfortunately many people are deficient in vitamin D. A recent study looked at the relationship between immunoreactivity to Epstein-Barr virus and a vitamin D deficiency in people with multiple sclerosis, and the study confirmed that vitamin D3 supplementation can limit the increase of EBV antibodies (29). Another study showed that vitamin D has a direct antiviral effect against viruses such as hepatitis C (30).
Vitamin C. Many people are aware that vitamin C can help with the immune system, which is why many people take vitamin C when dealing with the common cold. One study involving patients with elevated levels of EBV antibodies showed that high dose intravenous vitamin C therapy has a positive effect on the disease duration and causes a reduction of the viral antibody levels (31). Another study showed that vitamin C demonstrates an anti-viral immune response early in the infectious process, especially against the influenza virus (32).
Curcumin. There are thousands of studies which show the different benefits of taking curcumin, and a number of these demonstrate its effectiveness against different types of viruses. One study showed that curcumin is an effective agent for the inhibition of EBV reactivation (33). Another study showed that curcumin inhibits the entry of hepatitis C into human liver cells (34). Another study showed that curcumin inhibits the infectivity of enveloped viruses, including the influenza virus (35). I think just about everyone can benefit from taking curcumin, and if you have a viral infection you definitely should consider taking this.
Resveratrol. Like curcumin, there is also plenty of research which shows the benefits of resveratrol. One study showed that resveratrol inhibits the proliferation and survival of EBV-associated B-cell malignancies (36). Another study demonstrated the inhibitory effects of resveratrol on the Epstein-Barr virus lytic cycle, and thus suggests that it may be useful for preventing the proliferation of the virus (37). Yet another study showed that resveratrol may prevent EBV-associated lymphoproliferative diseases (38). Another study showed that resveratrol was found to inhibit herpes simplex virus types 1 and 2 (39).
Green Tea. Drinking green tea can also help with viruses. One study showed that the catechins in green tea have an antiviral effect on the influenza virus (40). Another study showed that the green tea polyphenol epigallocatechin-3-gallate (EGCG) inhibits hepatitis C virus entry (41). Another study showed that green tea catechins can inhibit adenovirus infection (42). And so this is yet another reason why drinking a few cups of green tea per day can be beneficial.
Lemon balm. Many people with hyperthyroidism and Graves’ Disease take lemon balm, but most don’t realize that it can potentially have antiviral effects. One study showed that lemon balm has an inhibitory activity on Herpes simplex virus type 2 replication (43). Another study showed that lemon balm can exert a direct antiviral effect on herpes viruses (44).
Garlic. Many people are aware that garlic has antibacterial effects, but a few studies also show that it has antiviral activity (45) (46). One of these studies determined that the compound ajoene has the most antiviral activity, followed by allicin (46).
Essential oils. A few studies have shown that certain essential oils can have antiviral properties. One study looked at the antiviral effect of 12 essential oils on herpes simplex virus type 1 replication, and found that lemongrass was especially effective at inhibiting the viral replication, even at low concentrations (47). Another study demonstrated the antiviral effect of peppermint oil on herpes simplex virus type 1 and type 2 (48). Another study showed that an essential oil blend significantly weakens virus infection (49).
So hopefully you have a better understanding of how a virus can cause an autoimmune thyroid condition such as Graves’ Disease and Hashimoto’s Thyroiditis, and what you can do to help inhibit the viral replication. The most important thing you can do is to improve the overall health of your immune system by eating well, managing your stress levels, getting enough sleep each night, and minimizing your exposure to environmental toxins. You want to make sure your vitamin D levels are over 50 ng/mL, and if you have a viral infection you might want to consider taking higher doses of vitamin C, along with curcumin, resveratrol, and garlic. Consider drinking a few cups of green tea each day, and perhaps look into using essential oils.