Designing individual treatments for coeliac disease
Media Release, Friday 20 July 2007
Treatments individually tailored to the 200,000 Australians with coeliac disease are now closer following Victorian research into the molecular workings behind the disease.
Although often overlooked or misdiagnosed, coeliac disease is readily diagnosed by a combination of blood tests and biopsy of the small intestine. The only currently available treatment is a diet free of gluten – the main protein in wheat, rye and barley grains. In people with coeliac disease, gluten inflames and damages the lining of the small intestine, hampering its ability to absorb nutrients from food.
People’s susceptibility to coeliac disease is determined by two major genes – DQ2 and DQ8. DQ2 genes are common in people in North America, Europe and Australia. About 95 per cent of coeliac patients have DQ2. In China and East Asia, the DQ2 genes are rare while the DQ8 genes are as common as in Europe. Although there is a commonly-held belief that coeliac disease doesn’t occur in East Asia and China it is likely that as Asian diets become more Western and therefore include more wheat – people diagnosed with the disease will increase.
When people with coeliac disease encounter gluten – a protein found in wheat-based breads – their body’s immune response is switched on and damage is done to the intestine. It had been assumed that the molecular workings underpinning this immune response in the DQ2 and DQ8 forms of the disease were similar and that any potential treatments could apply equally to both forms.
However, scientists from the Walter and Eliza Hall Institute (WEHI), Monash University and The University of Melbourne have found this is not the case.
The team of Ms Kate Henderson and Professor Jamie Rossjohn from Monash, Dr Jason Tye-Din and Dr Robert Anderson from WEHI, Professor Jim McCluskey from Melbourne University and others discovered that the immune response in people with the DQ8 form of coeliac disease was quite different to that of DQ2. Their findings are published in the current issue of the international journal Immunity.
Dr Anderson said crucial to the research was the discovery that T-cells (white blood cells that play a critical role in the immune response) in people with DQ8-associated coeliac disease reacted quite differently to the small proteins in gluten than the T-cells in people with the DQ2 from of the disease.
“At the molecular level there’s quite a different immune response to the gluten,” Dr Anderson said. “It is sufficiently different to the reaction with DQ2 that different therapies would be appropriate for people with the DQ8 form of coeliac disease.”
At the moment a gluten-free diet is the only treatment for coeliac disease. However nearly half the people on the diet still have damage to their small intestine. Consequently other therapies, including a vaccine and three different drugs, are in various stages of development.
The research team believes coeliac disease might be the first example of an immune disease where treatments are customised according to the genetic make-up of the patient.
“When developing drugs for coeliac disease you have to take into account people’s genetic background,” Dr Anderson said. “Until four years ago no-one was using the gene test for coeliac disease. Now it’s the most commonly requested genetic test for any medical condition in Australia.
“Now that we know what’s happening at a molecular level in both the DQ2 and DQ8 forms of the disease that genetic test will tell patients with coeliac disease and their doctors what treatment they will most benefit from.”
Please note: A patient with coeliac disease is available for interview and photographs. To arrange an interview contact Ms Penny Fannin on 0417 125 700.
Professor Jim McCluskey is available for interview on +61 8344 5709
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