High thyroid antibodies are commonly used to make a diagnosis of autoimmune thyroid disease including Hashimoto’s thyroiditis.
But are elevated thyroid antibodies a reliable indicator of autoimmune Hashimoto’s disease?
Recent studies show that in fact, you can have Hashimoto’s disease and test negative for thyroid antibodies.
This finding has two major implications:
First, there is an increased risk to miss the diagnosis when using thyroid blood tests alone for Hashimoto’s screening even if they include testing for thyroid antibodies.
Second, low or negative thyroid antibodies can give a false sense of Hashimoto’s being “cured” or going into remission when in fact your immune system continues to malfunction and your thyroid gland is being destroyed under the active autoimmune attack.
Here is why this can happen to you.
There are 2 types of thyroid antibodies that are commonly found in patients with Hashimoto’s disease:
1.Thyroid Peroxidase or TPO antibodies
Thyroid peroxidase (TPO) is a key enzyme necessary for the production of thyroid hormones and a major autoantigen in autoimmune thyroid disease.
High levels of TPO thyroid antibodies are a hallmark of Hashimoto’s disease and are present in up to 95% of patients who get this diagnosis.
Presence of TPO antibodies show correlation with the amount of lymphocytic infiltration in Hashimoto’s thyroiditis and can be found in 12-26% of people who have other thyroid lab results within the normal reference range.
2.Thyroglobulin or Tg antibodies
When inflammation of the thyroid gland causes follicular destruction, it can result in thyroglobulin (Tg) leaking into the blood stream. This can trigger the formation of Tg antibodies. However, anti-thyroglobulin antibodies are not as indicative for Hashimoto’s disease diagnosis because they are present in only between 20% and 50% of patients.
Why Thyroid Antibodies Are So Important
Many researches agree that elevated TPO and Tg thyroid antibodies precede the hypothyroidism diagnosis and can be useful early indicators of autoimmune thyroid disease. The progression from Hashimoto’s to hypothyroidism occurs gradually and it can take up to 10 years until hypothyroidism can be diagnosed using the TSH test.
There are 6 groups of people who show a high incidence of thyroid antibodies and can be considered high risk to develop Hashimoto’s disease at some point of their lives.
However, thyroid antibodies cannot always be reliably used for diagnosis of Hashimoto’s. There is an interesting fact that about 5 % of patients who have Hashimoto’s thyroiditis diagnosis based on clinical examination or ultrasound data have no measurable thyroid antibodies.
People who test negative for thyroid antibodies are more likely to be labeled as non-Hashimoto’s and remain undiagnosed
In fact, there are research studies that show that Hashimoto’s without high thyroid antibodies is indeed possible.
Hashimoto’s With Negative Thyroid Antibodies
Currently there are 3 possible explanations to why antibodies can be low or even negative but you can still have Hashimoto’s disease:
1. Early Stage Of The Disease
In one study based on the ultrasound and FNA biopsy researches of Thyroid Multidisciplinary Clinic from the University of Wisconsin came to the conclusion that many of their patients that came for the investigation of their thyroid health issues already had Hashimoto’s with or even without their thyroid antibodies elevated and TSH in the normal reference range.
Their findings indicate that:
Inflammatory infiltrations in the thyroid gland indicative of Hashimoto’s thyroiditis actually occur first and only then thyroid antibodies can become elevated
This means that in very early stages of the disease the damage to the thyroid has already begun while the thyroid antibodies may not be present yet. I wrote about this study in more detail here
2. Stressed And Weakened Immune System
Another reason for low or absent thyroid antibodies in Hashimoto’s can be the state of the immune system.
Negative thyroid antibodies can occur when a person has had Hashimoto’s thyroiditis for a long time but in the process of fighting the disease the immune system became so weak that it became unable to produce thyroid antibodies. The total B-cells and white blood cells counts become too low to be able to make antibodies.
3. Th-1 Dominance And Th-2 Suppression
Your immune system has two sides Th-1 and Th-2 that regulate its system response to the invaders. When Th-1 goes too high it suppresses Th-2 which is responsible for the antibodies production. This can result in thyroid antibodies being low or negative on the lab test results.
A more thorough investigation of the immune system can help to understand what is happening. Inflammatory cytokine such as IL-2, IL-12, TNFa and interferon are the compounds that build the Th-1 system. Another useful indicator for the state of your immune system is the CD4/CD8 ratio which is the ratio between T-suppressor and T-helper immune cells.
When inflammatory cytokines are high and the CD4/CD8 ratio is out of balance, this situation indicates an inflammation that results in the suppression of the Th-2 side of the immune system and negative thyroid antibodies even when Hashimoto’s thyroiditis is present.
This means that thyroid antibodies are not always a reliable marker for Hashimoto’s thyroiditis. It is not suitable to make a diagnosis at any stage of the disease and often an investigation of the immune system is necessary. There are 3 Autoimmune Tests that can be used for this purpose.
As Hashimoto’s progresses your autoimmune response can change and as a result you can test positive or negative at different times. However, this may not be a sign of recovery or that you don’t have Hashimoto’s disease.
In fact, often it gets worse before it gets better. People with a suppressed immune system won’t feel better and don’t test positive for thyroid antibodies until their immune system improves and actually only then starts to produce thyroid antibodies.
5 Signs Of Hashimoto’s Remission
1.Your symptoms subside or disappear. No more anxiety, depression, weight gain, heart palpitations, constipation, water retention and fatigue.
2. You may experience repair of some damage that was caused by Hashimoto’s like re-growth of hair and outer part of the eyebrows, healed intestinal lining, shrinking of the goiter and your were able to lose some weight.
3. Your metabolism is up and running. This means that your body temperature is ideally above 98 F and remains relatively stable throughout the day. Resting pulse is at the level of 80+ beats per minute for most people. You are no longer having cold hands and feet.
4. You don’t show intolerances to common foods any more and were able to safely re-introduce them back into your diet. You can tolerate more foods and your diet is not a restrictive diet that is difficult to maintain.
5. You have energy to perform your daily tasks and do some exercise.
Not there yet? Check out this hypothyroidism treatment that can help you achieve these results.
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Thyroid peroxidase autoantibodies in euthyroid subjects. Pract Res Clin Endocrinol Metab. 2005 Mar;19(1):1-15.
Patients with Hashimoto’s thyroiditis and negative thyroid antibodies have a milder form of the disease. Thyroidology for the Public, Vol 7, Issue 9, p.10-11