Use of Immune Checkpoint Inhibitors in Solid-Organ Transplant Patients: An Orphan Issue.

Immune checkpoint inhibitors block inhibitory signals on T cells, enabling the immune system to fight cancer cells more effectively. Immune checkpoints such as programmed cell death protein 1/programmed cell death ligand 1 and cytotoxic T-lymphocyte-associated protein 4 normally limit the immune response, preventing excessive immune reactions. However, cancer cells can evade the immune system by using these signals. Immune checkpoint inhibitors restore T-cell activity by blocking these escape mechanisms and by directing them to destroy cancer cells. Patients undergoing solid-organ transplant must use immuno-suppressive drugs lifelong to prevent organ rejection. Immunosuppressive therapies are necessary for the protection of the transplanted organ, but a potential risk of organ rejection occurs during the use of immune checkpoint inhibitors. In this review, we examined how immune checkpoint inhibitors are used in cancer treatment for transplant patients and the challenges encountered. We examined the effects of treatment on organ rejection, clinical cases that have resulted in success or complications, and future research directions.