Importance of T cells in the prevention of autoimmune diseases

Centenary scientist Associate Professor Barbara Fazekas de St. Groth, a leader in inflammatory bowel disease research, has demonstrated for the first time the important role of T cells in the prevention of autoimmune diseases in humans.

In a study involving 38 patients with Crohn's disease and ulcerative colitis, the two common forms of inflammatory bowel disease (IBD), and 43 healthy controls, Assoc Prof Fazekas and colleagues found that healthy individuals have up to twice the number of disease-fighting regulatory T cells compared with IBD patients at the onset of disease.

"It is important to have more regulatory T cells, especially when you are young, as individuals with a deficiency are more susceptible to disease and frequency of disease is higher in the young," says Assoc Prof Fazekas.

"Our results also indicate that the activity of these cells is increased in IBD patients during the later stages of disease in an attempt to fight it."

IBD is usually diagnosed in children and young adults. It affects 1 in 200 people and an estimated 100,000 Australians and there is no cure.

"Regulatory T cells have previously been difficult to quantify in humans and conventional methods could identify fewer than a third of the total number. The blood test we have developed allows us for the first time to accurately count the number of regulatory T cells in the body," says Assoc Prof Fazekas.

The highly accurate identification and isolation of regulatory T cells was made possible using sophisticated flow cytometry equipment at the Centenary Institute.

The machines use laser beams and advanced optics and electronics to analyse and purify many kinds of cells at a rate of over 25,000 cells every second. This technology is able to produce results that cannot be obtained by any other method as it allows every cell to be identified and sorted on an individual basis.

"The ability to detect regulatory T cell deficits in inflammatory diseases such as IBD means that we can now identify individuals at risk of developing disease. The test can also be used to assess the effect of new preventative treatments in the future."

The researchers are using the test to study regulatory T cell levels in autoimmune, inflammatory and allergic diseases such as multiple sclerosis, Type 1 diabetes, rheumatoid arthritis, asthma and eczema, to determine the risk of disease in patients and their families.

The study will be published in the July issue of The Journal of Experimental Medicine.