Since Crohn’s Disease (CD) and Ulcerative Colitis (UC) have been proposed to result from an overreactive immune response to the gut microbiome in genetically susceptible individuals, assessing the distribution of bacterial species within the intestines may contribute to an improved understanding of mechanisms regulating disease pathogenesis and lead to curative medical interventions.

Kiernan et al analyzed the distribution of bacterial phyla and species within the Mesenteric Lymph Nodes (MLNs) of UC and CD patients. MLNs are sites of immune cell trafficking and congregation within and near the intestines, representing important outlets for interaction between the gut microbiome and the immune system. While other studies have assessed the bacterial microbiome of fecal matter and the intestinal mucosa, this was the first project to explore whether the microbiome of MLNs differs between UC and CD patients.

These patient populations were indeed demonstrated to carry distinctly different bacterial populations. The MLNs of UC patients were enriched for Proteobacteria and those of CD patients for less common phyla such as Fusobacteria. The distribution of bacterial species was less diverse in CD patients, containing comparatively fewer types of bacteria. These findings regarding the mesenteric lymph node microbiome could be used to confirm the diagnosis of patients with indeterminate colitis and may shed light on mechanisms contributing to the development and progression of these inflammatory bowel diseases.

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Kiernan MG, Coffey JC, McDermott K, et al. (2019) The Human Mesenteric Lymph Node Microbiome Differentiates Between Crohn’s Disease and Ulcerative Colitis. J Crohns Colitis, 13(1):58-66.

https://academic.oup.com/ecco-jcc/article/13/1/58/5098279?searchresult=1













