(HealthDay News)  A total of 163 genetic loci are associated with inflammatory bowel disease, many of which are implicated in other immune diseases and in the response against bacterial infection, according to a study published in the Nov 1 issue of Nature.

Luke Jostins, from the Wellcome Trust Sanger Institute in Cambridge, UK, and colleagues performed a meta-analysis of Crohn’s disease and ulcerative colitis genome-wide association scans with validation of significant findings, including a combined total of 75,000 cases and controls.

The researchers identified 71 additional loci, bringing the total number of inflammatory bowel disease loci that meet genome-wide significance thresholds to 163. Most were linked to both Crohn’s disease and ulcerative colitis, and many were linked to other immune-mediated disorders such as ankylosing spondylitis and psoriasis. The loci associated with susceptibility to inflammatory bowel disease also overlapped with loci associated with the response to mycobacterial infection.

“Most of the evidence relating to possible causal genes points to an essential role for host defense against infection in inflammatory bowel disease,” Jostins and colleagues conclude. “In this regard, the current results focus ever-closer attention on the interaction between the host mucosal immune system and microbes, both at the epithelial cell surface and within the gut lumen.”

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