"We have greatly expanded the map of genetic regions that are associated with IBD", agreed Dr. John Rioux, co-lead author of this study and chair of the Consortium, with Jeffrey Barrett of the Wellcome Trust Sanger Institute in Cambridge, England, lead author of the study. "Each of these regions only increases a person's chance of developing IBD by a fraction of a per cent and even taken together they cannot tell us who will or will not develop the disease. But they each tell a small story about the biology of this disorder, and by combining them we find biological pathways that, if disrupted, can lead to IBD."
Immune system: a major factor
Dr. Rioux and the international team of researchers also studied the activity of genes in their IBD regions in hundreds of different types of cells involved in the immune system. They found that certain cells tended to produce more of these IBD genes, including many that are involved in the body's first line defence against invasion. This illustrates that an immune response seems to be a major factor in IBD: when a bacterium is detected, these cells are not just activated, but become overactive.
"We see a genetic balancing act between defending against bacterial infection and attacking the body's own cells," said Dr. Barrett. "Many of the regions we found are involved in sending out signals and responses to defend against bad bacteria. If these responses are over-activated, we found it can contribute to the inflammation that leads to IBD."
Nearly 100 scientists in 15 countries
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| Contact: William Raillant-Clark w.raillant-clark@umontreal.ca 514-343-7593 University of Montreal Source:Eurekalert |