A microbe-dependent viral key to Crohn's box.

Once Pandora unlocked her fateful box and liberated the evil forces within, it became impossible to put them back. Now, new work on Crohn's disease suggests the existence of a viral "key" that irreversibly renders a genetically susceptible mouse prone to pathogenesis. Indeed, dangerous liaisons among host genotype, viral infection, intestinal injury, and trillions of gut microbes may in part determine which individuals progress to a full-blown disease state. These findings suggest that viral and bacterial triggers may serve as therapeutic targets for Crohn's and prompt new hypotheses that relate inflammation, host immune status, microbial community structure, and human health.