Gut Microbiome and Immune Checkpoint Inhibitor-Induced Enterocolitis

The gut microbiome is increasingly being described as one of the underlying mechanisms for development of immune checkpoint inhibitor (ICI)-induced colitis. Similarities in gut microbiome profiles have been found among various diseases associated with intestinal inflammation, including inflammatory bowel disease. Certain bacterial species have been reported to be preventive for colitis, as well as beneficial for cancer outcome, in patients receiving ICI therapy. Alternatively, other bacterial classes have been shown to be associated with immunologic alterations causing intestinal inflammation with subsequent increase in the risk of ICI-related colitis. Gut microbiome manipulation by fecal transplantation has been proposed as one of the modalities to ameliorate inflammation in patients with ICI-related colitis refractory to immunosuppressive therapy. Additional investigations are needed to clarify the role of gut microbiome in the pathogenesis of ICI-related colitis.