Application of Immune Checkpoint Inhibitors in Solid Organ Transplantation Recipients: A Systematic Review

Solid organ transplantation (SOT) is a treatment method for end-stage organ diseases and improve their life quality, while using long-term immunosuppressant drugs (ISD) is needed to suppress the function of the immune system. Immune checkpoint inhibitors (ICIs) are a class of anti-tumor drugs that kill tumors by activating the autoimmune system. The primary objective of our systematic review is to investigate the risk factors for organ rejection and the efficacy of ICIs in solid organ transplantation recipients (SOTRs).

We searched four databases to find relevant articles up to January 2021. A total of 61 articles involving 106 SOTRs met the screening criteria and were included in our systematic review. The collected data were statistical described, and the risk factors were analyzed by logistic regression.

Forty-four patients (41.5%) developed host-versus-graft response (HVGR) after ICIs. mTOR inhibitors (pre-ICIs) (p = 0.069, OR = 0.377, 95% CI 0.132-1.078) and calcineurin inhibitors (post-ICIs) (p = 0.056, OR = 0.375, 95%CI 0.137-1.025) may help reduce the incidence of HVGR. Hormones (pre-ICIs) (p = 0.026, OR = 3.150, 95%CI 1.150-8.628) and anti-metabolites (pre-ICIs) (p = 0.022, OR = 3.214, 95%CI 1.185-8.720) may adversely affect the efficacy of ICIs. Only 35.6% of patients both responded well to ICIs treatment and did not develop HVGR.

Our systematic review summarizes the use of ICIs in SOTRs and evaluates the efficacy of ICIs and the risk factors that induce HVGR. Through risk factor analysis, we found that mTOR inhibitors and calcineurin inhibitors may help to reduce the occurrence of HVGR; hormones and anti-metabolic drugs may have adverse effects on the efficacy of ICIs. In addition, there is a contradictory relationship between the occurrence of HVGR and the efficacy of ICIs.