The Intestinal Microbiota and Therapeutic Responses to Immunotherapy

The intestinal microbiota, a complex ecosystem of microorganisms, has emerged as an important player in modulating various aspects of human health and disease. The microbiota is in a state of constant cross talk with itself and its host, and these interactions regulate several aspects of host homeostasis, including immune responses. Studies have demonstrated a relationship between the microbiota and outcomes of several cancer immunotherapies. This review explores the different roles of intestinal microbiota in shaping the efficacy and safety of cancer immunotherapies, including allogeneic hematopoietic cell transplantation, immune checkpoint blockade, and CAR T cell therapy.