Gut microbiota influences the efficiency of immune checkpoint inhibitors by modulating the immune system (Review)

Abstract

Immune checkpoint inhibitors (ICIs) are commonly utilized in tumor treatment. However, they still have limitations, including insufficient effectiveness and unavoidable adverse events. It has been demonstrated that gut microbiota can influence the effectiveness of ICIs, although the precise mechanism remains unclear. Gut microbiota plays a crucial role in the formation and development of the immune system. Gut microbiota and their associated metabolites play a regulatory role in immune balance. Tumor occurrence and development are linked to their ability to evade recognition and destruction by the immune system. The purpose of ICIs treatment is to reinitiate the immune system's elimination of tumor cells. Thus, the immune system acts as a communication bridge between gut microbiota and ICIs. Varied composition and characteristics of gut microbiota result in diverse outcomes in ICIs treatment. Certain gut microbiota-related metabolites also influence the therapeutic efficacy of ICIs to some extent. The administration of antibiotics before or during ICIs treatment can diminish treatment effectiveness. The utilization of probiotics and fecal transplantation can partially alter the outcome of ICIs treatment. The present review synthesized previous studies to examine the association between gut microbiota and ICIs, elucidated the role of gut microbiota and its associated factors in ICIs treatment, and offered direction for future research.

Keywords: fecal transplantation; gut microbiota; immune checkpoint inhibitors; immune system; immunotherapy; probiotics.

Figure 1.

The role of gut microbiota in ICIs. Some members and characteristics of gut microbiota can enhance the efficiency of ICIs, while others can weaken it. According to different reports, some metabolites related to gut microbiota can enhance the efficiency of ICIs, while others can attenuate the efficiency of ICIs. The application of antibiotics in general attenuates the efficiency of ICIs. In general, the application of probiotics can enhance the efficiency of ICIs, but some studies have reported that the application of probiotics can weaken the efficiency of ICIs. Fecal transplantation can enhance the efficiency of ICIs. ICIs, immune checkpoint inhibitors.