The Microbiota and the Immune Response: What Is the Chicken and What Is the Egg?

Abstract

The underlying factors driving the onset and progression of inflammatory bowel disease (IBD) include the interplay between host genetics, microbiota, and mucosal inflammation. The same environmental triggers that are a risk factor for IBD also alter the microbiota, suggesting a link between the microbiome and IBD. Specific IBD-associated genetic polymorphisms change the microbiome linking host genetics to the microbiota. Microbial changes occur at least simultaneously with new onset IBD, and fecal microbial transplant can ameliorate certain types of IBD. A current debate in the field is which comes first, dysbiosis or inflammation? Can restitution of the microbiome "cure" IBD?

Keywords: Bacterial translocation; Colitis; Crohn’s disease; Dysbiosis; Host-microbe interactions; Innate immunity; Intestinal inflammation; Ulcerative colitis.