Regulatory T cell

Regulatory T cells (Tregs) are anti-inflammatory. They produce the anti-inflammatory cytokines TGF-β and IL-10. They suppress effector Th1, Th2, and Th17.

Dietary and environmental factors
Vitamin D improves regulatory T cell function in healthy adults and in patients with relapsing remitting multiple sclerosis (MS), suggesting that it may play a role in both preventing and ameliorating autoimmune disease.

Various species of probiotics have been shown to increase FoxP3 expression in animal models.

Chronic Fatigue Syndrome and ME/CFS
An Australian group found that Tregs were elevated in thirty individuals with Fukuda for chronic fatigue syndrome (CFS). The same group found elevated Tregs in a multiple sclerosis comparison study.

However, a study that used the Revised Canadian Consensus Criteria (2010) criteria found Tregs were depleted in 76 people with ME/CFS.

A second study in Japan also found decreased Tregs in 41 people who met both the Canadian Consensus Criteria and the International Consensus Criteria as compared to age- and gender-matched healthy controls.

It is worth noting that such seemingly contradictory results are often found in the systemic autoimmune diseases in which T cell subsets are often studied. Even in illnesses with well-established biomarkers, age, gender, and time since onset lead to significant variability.

Notable studies

 * 2018, Association of T and NK Cell Phenotype With the Diagnosis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)
 * 2017, Dysregulation of T and B cells in myalgic encephalomyelitis/chronic fatigue syndrome
 * 2016, Regulatory T, natural killer T and γδ T cells in multiple sclerosis and chronic fatigue syndrome/myalgic encephalomyelitis: a comparison.