Modulation of intestinal immune cell responses by eubiotic or dysbiotic microbiota in inflammatory bowel diseases

Background: Alterations of the gut microbiota have been linked to aberrant mucosal immune responses, leading to different intestinal and extraintestinal disorders, including inflammatory bowel diseases (IBD) in genetically susceptible hosts. Thus, restoration of immune homeostasis through the manipulation of the gut microbiota is now considered a possible therapeutic approach to treat IBD patients. Management of IBD patients is currently including the customization of microbe-targeted therapies, such as antibiotics, prebiotics, live biotherapeutics and faecal microbiota transplantation. In this narrative review, we will discuss recent advancements in the understanding of host-microbes interactions in IBD and the basis to promote homeostatic immune responses through microbe-targeted therapies. Methods: We interrogated with no limit of publication time, the PubMed and Scopus databases using the following keywords: microbiota, inflammatory bowel diseases, IBD, immune system, microbe-targeted therapies. Results: Therapeutic restoration of homeostatic immune function in IBD patients currently include the manipulation of the gut microbiota through antibiotics, prebiotics, probiotics, and faecal microbiota transplantation. Nonetheless, differences in efficacy has been reported according to existing microbe-targeted therapies, opening the venue for the search of novel approaches such as phage therapies and combinatorial therapies. Conclusions: Alterations in the composition of the gut microbiota have been implicated in a wide variety of pathologies, including IBD. Microbiome-modulating therapies have proven promising treatments targeting inflammation by modulating the microbiota to correct patients’ dysbiosis, normalize immune system responses and repair epithelial barrier deficiencies.