*Scientists Show How Immune System Chooses Best Way To Fight Infection
Prevention Is Better Than Cure: Fighting Autoimmune Diseases
11 Jul 2006
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.
http://www.medilexicon.com/medicalnews.php?newsid=46860∞
Scientists Show How Immune System Chooses Best Way To Fight Infection
18 Nov 2006
A new study has suggested a novel way of combating diseases related to the immune system, including cancer and autoimmune diseases such as type I diabetes and arthritis. The study, funded by the Wellcome Trust, appears online in the journal Nature.
T cells are produced by the body to fight infection. Scientists previously identified two types of T cell, both produced in the thymus: "effector T cells", which attack infected cells, and "regulatory T cells", which suppress the immune system, protecting the body from inflammatory damage during infection. Regulatory T cells, if given to individuals receiving transplants, may help suppress the rejection response.
Now, a team of researchers has discovered a novel mechanism determining whether a maturing T cell is likely to emerge from the thymus as an effector cell or a regulatory cell. The research suggests that new treatments could be developed to deliberately affect the type of T cells produced, allowing scientists to tackle a number of diseases which are influenced by these different types of T cells.
"Our team has shown that a process known as 'trans-conditioning', which we knew to be involved in T cell development, actually has a profound influence on whether a T cell becomes an effector or a regulatory cell," explains Professor Adrian Hayday of King's College London. "This may be clinically significant; if we can find a way to influence this process, it may be possible to make the body produce effector T cells in a cancer patient or regulatory T cells in someone suffering from autoimmune disease, both of which are caused by the immune system malfunctioning."
Professor Hayday and his team believe that the findings may also answer one of medical research's mysteries: why autoimmune diseases in women commonly go into remission in pregnancy.
"We believe that trans-conditioning is less active during pregnancy," says Professor Hayday. "This means that most T cells emerging at that time will be regulatory. Regulatory T cells prevent an over-active immune system from causing inflammatory damage to the body. This may be one of the key steps in preventing the mother from rejecting the foetus growing inside her."
http://www.medilexicon.com/medicalnews.php?newsid=56692∞
Note by Kathy - many women report that their symptoms subside during pregnancy, only to re-appear once the baby is born. Others have first symptoms following a pregnancy. Maybe this starts to explain why.