Incidental detection of operational tolerance in a deceased donor kidney transplant recipient lost to follow-up for more than 10 years: A case report and literature review.

Graft tolerance is a clinical state of absence of an immune response in the recipient toward a donor allograft without any exogenous immunosuppression. Although more prevalent in liver transplantation recipients, it has rarely been reported in renal transplant recipients. We present a 62-year-old deceased donor kidney transplant recipient who exhibited operational tolerance as they stopped immunosuppressant medications for more than 10 years and yet demonstrated stable graft function. Although various hypotheses, such as deletion, anergy, immunoregulation, and clonal exhaustion, have been experimentally validated, clinical "operational tolerance" of a renal allograft on a prolonged basis has been infrequently reported in the medical literature. This review intends to highlight possible etiologies and make clinicians aware of this possible rare condition to which more research is needed.