EBV May Be A Factor In Hashimoto's, Graves' Disease And Thyroid Cancer
∞ Epstein Barr Virus (EBV) has long been associated with thyroid disease. It has been implicated in everything from Hashimotos to thyroid cancer. As I have read through the research I find there is a continuing correlation between EBV and thyroid disorders. Several systemic autoimmune diseases have been demonstrated to be associated with chronically relapsing EBV infection and inefficient immune control of the virus. The evidence keeps piling up and there does seem to be some very obvious connections that need more attention.
What Is EBV
EBV is a large enveloped double stranded DNA virus and one of the 9 types of herpesvirus types in the herpes family. It is called Herpes 4 (herpes viruses are all numbered). It is one of the most common viruses in humans. There are several strains of EBV and individuals can become infected with two or more strains. Most people become infected with EBV at some point in their life. Luckily, it is asymptomatic in many people.
The EBV Infection
It has a primary infection, a latent or resting period and a reactivation phase. Chronic, relapsing EBV is when an old infection goes back-and-fourth from resting phase to active phase. EBV can infect both epithelial cells and B cells. It has been found in other areas also, but mostly resides in B cells and epithelial cells. Once you have EBV it remains in your body, but mostly in a dormant state. For many people who are infected in the first few years of life, the infection will stay dormant unless the immune system becomes dysfunctional (lowered) and allows it to reactivate. This could be due to old age, drugs, environmental toxins, or other illness that strains the immune system. A person can experience a chronic situation with exacerbations and periods of relief as it goes back-and-forth from latent to active infective states. This kind of relapsing illness is often seen in the family of herpes viruses.
Although younger people are often asymptomatic when they get EBV, older individuals can get symptoms that we call infectious mononucleosis. This is a prolonged state of fever, chills, aches, swollen lymph nodes, sore throat, reddened throat, cough, nausea and vomiting, rash, fatigue, loss of appetite, headache, photophobia, malaise as well as enlarged liver and spleen. This can last 2-4 weeks but in some cases may last for months and need immune support.
I have found a base herbal formula of Echinacea, Osha, Licorice and Red root is helpful for immune support in Mononucleosis, but not everyone can use Licorice due to side effects. Additionally, other herbs and supplements are often needed for the individual on top of this base formula.
When EBV reactivates after a latent period it is milder than the initial infection. It often looks flu-like, except it lasts a long time and there is no fever. The person usually has one or more of the following: fatigue, lymph node swelling, possible chronic sore throat, muscle and joint pain, may feel depressed, may find abnormal liver tests, abnormal serology for antibodies, or detection and quantification with PCR testing. Due to false negatives and positives, it is suggested by researchers that multiple types of testing be used to identify EBV reactivation. "Thus, to fully define the incidence and prevalence of EBV infection in a population, several assays should be used, preferably combining assays for detection of viral nucleic acids, Abs to different viral antigens and the frequency of virus-specific T cells.Optimally, different detection principles may also be used; e.g. for Ab detection: enzyme-linked immunosorbent assay (ELISA) and immunoblotting, for T cell detection: antigen-induced cytokine release and peptide-MHC tetramer assays, and the assays should target different parts of the viral genome or different viral antigens representing both latent and lytic states."
I would also add that other viruses can cause similar symptoms. A couple of examples would be Cytomegalovirus, and Toxoplasmosis.
Why One Person Gets EBV Reactivation And Another Does Not
The reason one person never has EBV reactivation while other people have reactivations over and over again is due to their level of immune response. The immune system forces the virus back into hibernation when it rears its ugly head. the immune system's ability to react depends on an individual’s genetics, other pathogens, the body's state of nutrition, environmental toxins and any other types of body stressors that may be affecting the immune system. One of the things that really taxes the immune system is stress. Being chronically overwhelmed and exhausted makes it more difficult for our body to contain infection and inflammation.
Epstein Barr Virus As Cause Of Thyroid Disease Through Autoimmunity
One of the implications is that EBV is causing autoimmune disorders in the thyroid gland as well as other autoimmune disorders such as Sjogren’s syndrome, Rheumatoid arthritis, Lupus and multiple sclerosis. The so called “autoimmiune thyroid disorders” are the most common of the organ-specific autoimmune diseases, affecting up to 10% of the world’s population.
Why EBV is Considered A Factor In Autoimmune Disease
- EBV is commonly found to be responsible for the worldwide prevalence of many autoimmune diseases.
- EBV stays in the body throughout life, and could therefore be associated with the chronic course of autoimmune diseases that are often accompanied by exacerbations of symptoms and quiet periods through-out life.
- EBV is known to modify the hosts immune response
Let's look at the theory of EBV autoimmunity and thyroid disease before moving on.
The Theory of EBV Thyroid Autoimmune Reaction
One hypothesis is that in genetically susceptible patients, EBV-infected autoreactive B-cells seed the thyroid gland, produce autoantibodies, and send co-stimulatory signals to autoreactive T-cells. Normally, the EBV infection is kept under control, especially by cytotoxic CD8+ T-cells that eliminate active EBV and infected B-cells that have virus hiding quietly inside them. Impaired EBV control may result from a decreased number of EBV-specific CD8+ T-cells. An increased CD4/CD8 ratio is characteristic of autoimmune diseases
The Theory of Autoimmunity
The idea of autoimmunity is that our bodies are mistakenly attacking themselves for one of a variety of reasons that we will briefly examine. However, could it be that the EBV virus or other viruses may actually be responsible for the changes and damages in the immune system as well as the direct damage caused to organ tissues such as the thyroid, rather than the immune system turning on itself. Perhaps it is not an immune system run amok, but an immune system that is continually having to protect us from EBV or other viruses, and our tissues end up with collateral damage. Is the idea of decreasing the immune system's activity (that is believed to be running amok) setting us up for further long-term damage from the EBV or other viruses? This is a question some physicians are asking. I personally don't know, but I do know that the body does make antibodies to its own tissue in autoimmunity as we can measure them, so it is hard to believe these antibodies are not causing tissue damage. In this article we will take a look at what EBV is and how it is known to affect the thyroid. In a later article, we will examine what can be done about EBV and how we can support the thyroid gland.
Theoretical Mechanisms Thought To Cause Autoimmunity
- Molecular mimicry: when the virus or other microbe has peptide structures on their bodies that look similar to peptides in our own bodily tissues and our body is thought to attack our own tissue peptides thinking they are the virus peptides.
- Enhanced processing and presentation of auto-antigens: Antigen-presenting cells are recruited to an inflammatory site and followed by autoreactive lymphocyte priming
- Bystander Effect: enhanced cytokine production that induces the expansion of autoreactive T cells.
- Activation of lymphocytes by lymphotropic viruses: an infection of B cells resulting in B cell proliferation. There is excess antibody production, and increased formation of circulating immune complexes.
- Viral and bacterial superantigens: activation of autoreactive T cells that express particular Vβ segments
EBV Is Associated With A Variety Of Diseases
Although most of the research is looking at Hashimotos and EBV, it appears other disorders are also associated with EBV or can be triggered by EBV. Grave’s disease (a hyperthyroid disease) as well as the growth of cancers, which are correlated with EBV. It is not just thyroid cancer that has been implicated, EBV has been associated with other tumors such as gliomas and lymphomas too. Researchers theorize that this may be related to an inherent ability of EBV to cause transformation of B cells and epithelial cells into carcinogenic cells. (EBV is largely found in B cells and epithelial cells) I would add that EBV is also not the only virus connected with cancer as other viruses have also been implicated in cancer.
Is EBV the agent responsible for development of these cancers and "Autoimmune" thyroid diseases or is it a coincidental infection? Evidence of EBV is found in 90-95% of adults, so this is a fair question to ask. Research indicates that 10-15% of human cancers are caused by infection from several types of viruses. These include papillomavirus, hepatitis B virus, human herpes virus 8 and Epstein-Barr virus (EBV) and RNA viruses such as human T-cell lymphotropic virus type 1 and hepatitis C virus.
In the case of EBV, researchers originally thought that when the virus is in a lytic state (active and infective) that this was when infection related disease such as cancer or "autoimmune" disease took place. In the past researchers thought EBV was not hazardous in a latent (resting) state. However, more recent research claims latent EBV appears to be involved in instigating cancer.
This is certainly not something well understood. Indeed it does appear that EBV is a contributory factor in cancer and "autoimmune" diseases, but it also appears other pathogens, genetics and environmental factors play a role.
Scientific Evidence Connecting EBV And Thyroid Disease
- Both Hashimotos and Graves Disease have shown a high prevalence of EBV infection and EBV is considered to be a potential etiologic organism in autoimmune thyroiditis.
- Testing of thyroid nodules for various viruses using PCR has found EBV DNA sequences. In one study 16% of thyroid nodule samples found EBV DNA in the nodules.
- In another study looking at Epstein-Barr Nuclear Antigen 1 (EBNA1) gene in papillary thyroid carcinoma tissue they found EBNA1 in 65.8% of the 41 samples. It was higher in those with younger ages leading the researchers to think EBV is associated with papillary thyroid carcinoma in younger ages.
- There is a case report of a thyroid storm precipitated by EBV.
- EBV-associated with lymphepithelioma-like thyroid carcinoma.
- B cell lymphomas and nasopharyngeal epithelial carcinomas, affecting the two primary cell types targeted by the virus, are caused by EBV.
EBV may participate in the malignant transformation of Hashimoto’s disease into malignant lymphoma of the thyroid.
Disease Examples Associated With EBV
- Burkitt's lymphoma
- Hodgkin's lymphoma
- Hemophagocytic lymphohistiocytosis
- Nasopharyngeal cancer
- Gastric cancer
- Inflammatory Bowel disease
- Autoimmune disease in general, but specifically:
- Systemic Lupus erythematosus
- Rheumatoid arthritis
- Sjogren's syndroms
- Multiple sclerosis dermatomyositis
- Hashimoto's disease
- Grave's disease
Other Pathogens Implicated Through Research As Factors In Causing Thyroid Disease
This list keeps growing as more research is completed. These are are all possible factors in thyroid disease.
Involvement of Genetics and Environmental Factors
According to Hansen et al., between 60% and 70% of autoimmune thyroid disorders are genetic-related. Family and twin studies suggest that development of thyroid autoantibodies in first-degree relatives of patients with autoimmune thyroid disease is under genetic influence.
The cause of Hashimoto's disease and Grave's disease as well as thyroid cancer is certainly not known for sure, but the research keeps building up that EBV and perhaps even other pathogens have a causative role in their presence.
Identifying reactivation of EBV and other viruses/pathogens is not always easy to do and needs thorough testing to identify. If you think you have chronic EBV it would be good to find out as it is associated with a lot of possible complications.
Seeking out advice from a naturopath, functional medicine MD or other alternative practitioner to support your immune system would be beneficial if you do have chronic EBV. As I have time, I will write a further article on this to give you some ideas on immune support and protecting your body from EBV.
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