T Regulatory Cells and Autoimmune Thyroid Disease
Our immune systems are complicated things, that is for certain. They contain a variety of different cells that can kill pathogens with a memory as sharp as a razor, keeping our bodies protected from disease. They are a small army, constantly patrolling our bodies for invaders and sending signals to other cells when a threat is detected. In some instances however, something goes wrong with our immune system, and the immune system can attack our own “self” tissue, which is what happens in autoimmune disease.
T Cells - What Are They?
The T-cells are a type of white blood cell that mature in the thymus (a gland located behind the sternum) and tonsils. There are several different types of T cells including : T helper cells (these assist other cells by secreting cytokines that activate different killing mechanisms in the immune system), Cytotoxic T Cells (these cells do just what they sound like they do – they secrete toxic substances to destroy virally infected cells and cancer cells, Memory T Cells (these keep within them a memory of past infections so if reinfection occurs, the action of the immune system is swift), Natural Killer T Cells (these can perform actions similar to the T helper and the Cytotoxic T cells), and finally: Regulatory T Cells.
Regulatory T cells are the cells that keep everything in the immune system under control.
Regulatory T Cells shut off the immune response once it has finished it’s work, and are required for something known as immunological tolerance. Immunological tolerance is important for normal physiology, in that if our immune systems see our own tissues as a foreign substance to be attacked, we are in serious trouble.
Autoimmune Disease and T Regulatory Cells
In patients with autoimmune disease, this function has gone awry. When the immune system attacks self tissues,a variety of autoimmune diseases result, depending on the organ that is being targeted. It’s well known that patients with autoimmune disease have dysfunction of the regulatory T cells (Also known as CD4+ CD25% T Cells).
Typically, T regulatory cells that have a high surface expression of what is known as CD25+ (a special type of receptor on the surface of the cell) are known to be the most effective in regulating the immune response when it is needed.
A recent study looked at a group of patients with Hashimoto’s Thyroiditis, and Graves disease (these are two autoimmune thyroid diseases – where the immune system attacks the body’s own thyroid gland) and compared them to patients that had a non-autoimmune enlarged thyroid (goitre).
The study found that patients with Hashimoto’s Thyroiditis and Grave’s Disease had significantly lower levels of the T regulatory cells with CD25+ expression. Without these important cells, the autoimmune process goes unchecked, and precious thyroid cells are destroyed.
What can be Done to Improve T-Regulatory Cell Numbers?
Astragalus is a herb that been found to substantially increase CD4+ CD25+ T cells.
Multiple studies have found that having good levels of Vitamin D will support healthy T regulatory cell function with good CD25+ expression. Autoimmune diseases such as multiple sclerosis have been associated with Vitamin D deficiencies. Taking Vitamin D and having levels checked is important for patients with Hashimoto’s or Grave’s Disease. A good target level for Vitamin D for patients with autoimmune disease is 70 ng/ml or 175 nmol/l.
A recent study investigating the effects of grapeseed extract on mice with Rheumatoid Arthritis found that grapeseed extract effectively upregulated the production of T regulatory cells and produced an anti-inflammatory response.
Curcumin is an active component of the spice, turmeric. It has a remarkable anti-inflammatory profile and has been shown to significantly increase T reg populations. If you are trying to conceive however, it’s best to avoid curcumin since it’s a contraceptive. As curcumin is poorly absorbed from food sources, specific extracts may be most useful clinically. One absorbable form that I like is Theracurcumin.
This is a complicated topic and one I will likely address with its own blog post fairly soon. Different strains of probiotics appear to have different effects when it comes to stimulating the immune system. As you can imagine, a bacteria can be a profound stimulator of immune mechanisms and as such much research is being done into the use of probiotics in the regulation of the immune response. A highly detailed study recently found that S. thermophilus 1342, Lb. casei 290, Lb paracasei 292, S. thermophilus M5, Lb. delbrueckii ssp. bulgaricus 11842, B. lactis BB12, Lb. rhamnosus G5434, Lb. rhamnosus 5434, Lc. lactis , Bifidobacterium spp. (BL1941, BB12 and BB99), and Lb. salivarius 5248, all demonstrated a significant ability to induce CD25+ T regulatory cells, potentially beneficial for those with autoimmune diseases.
EGCG, an active component of Green Tea has been associated with increased Treg populations in lympoid tissues and in the central nervous system. This may explain it’s beneficial anti-inflammatory effects for patients with autoimmune disease.
What to Avoid if you Have low T-Regulatory Cells?
A recent study found that echinacea works in part by reducing the action of T regulatory cells. This is one way in which it elicits an immune response against pathogens.
A recent study found that DHA reduces the suppressive and migratory functions of CD4CD25+ regulatory T cells. It’s important to note however that this is different from taking a whole food source of fish oil or fermented fish oil, which often is EPA dominant and can have the beneficial effect of increasing T regulatory cell function.
- Han SC, Kang GJ, Ko YJ, Kang HK, Moon SW, Ann YS, Yoo ES. Fermented fish oil suppresses T helper 1/2 cell response in a mouse model of atopic dermatitis via generation of CD4+CD25+Foxp3+ T cells. BMC Immunol. 2012 Aug 9;13:44.
- Huang X, Tang L, Wang F, Song G. Astragaloside IV attenuates allergic inflammation by regulation Th1/Th2 cytokine and enhancement CD4(+)CD25(+)Foxp3 T cells in ovalbumin-induced asthma. Immunobiology. 2014 Jul;219(7):565-71. doi: 10.1016/j.imbio.2014.03.005. Epub 2014 Mar 20
- Nada AM, Hammouda M. Immunoregulatory T cells, LFA-3 and HLA-DR in autoimmune thyroid diseases. Indian J Endocrinol Metab. 2014 Jul;18(4):574-81.
- Prietl B, Treiber G, Mader JK, Hoeller E, Wolf M, Pilz S, Graninger WB, Obermayer-Pietsch BM, Pieber TR. High-dose cholecalciferol supplementation significantly increases peripheral CD4⁺ Tregs in healthy adults without negatively affecting the frequency of other immune cells. Eur J Nutr. 2014 Apr;53(3):751-9.
- Yessoufou A, Plé A, Moutairou K, Hichami A, Khan NA. Docosahexaenoic acid reduces suppressive and migratory functions of CD4+CD25+ regulatory T-cells. J Lipid Res. 2009 Dec;50(12):2377-88.
- Wu D, Wang J, Pae M, Meydani SN. Green tea EGCG, T cells, and T cell-mediated autoimmune diseases. Mol Aspects Med. 2012 Feb;33(1):107-18. doi: 10.1016/j.mam.2011.10.001. Epub 2011 Oct 14.