Microbiome and Gluten

Celiac disease (CD) is a frequent chronic inflammatory enteropathy caused by gluten in genetically predisposed individuals that carry disease susceptibility genes (HLA-DQ2/8). These genes are present in about 30-40% of the general population, but only a small percentage of carriers develops CD. Gluten is the key environmental trigger of CD, but its intake does not fully explain disease onset; indeed, an increased number of cases experience gluten intolerance in late adulthood after many years of gluten exposure. Consequently, additional environmental factors seem to be involved in CD. Epidemiological studies indicate that common perinatal and early postnatal factors influence both CD risk and intestinal microbiota structure. Prospective studies in healthy infants at risk of developing CD also reveal that the HLA-DQ genotype, in conjunction with other environmental factors, influences the microbiota composition. Furthermore, CD patients have imbalances in the intestinal microbiota (dysbiosis), which are not fully normalized despite their adherence to a gluten-free diet. Therefore, it is hypothesized that the disease can promote dysbiosis that aggravates CD pathogenesis, and dysbiosis, in turn, can initiate and sustain inflammation through the expansion of proinflammatory pathobionts and decline of anti-inflammatory mutualistic bacteria. Studies in experimental models are also contributing to understand the role of intestinal bacteria and its interactions with a predisposed genotype in promoting CD. Advances in this area could aid in the development of microbiome-informed intervention strategies that optimize the partnership between the gut microbiota and host immunity for improving CD management.