AHR and inflammatory bowel disease: Patients with IBD showing enormous quantitative and qualitative changes in the intestinal mucosa-associated microbiome, as assessed by 16S rRNA sequencing, during remission vs. active flares of the disease, which may not only affect the ensuing immune response by the antigen repertoire expressed, but also by the kind of microbiome-produced metabolites, e.g., short-chain fatty acids or Ahr agonists [108].