Renal allograft rejection after treatment with nivolumab in patients with metastatic renal cell carcinoma.

In recent years, immune checkpoint inhibitors (ICIs), such as nivolumab, pembrolizumab and ipilimumab, have been introduced into routine clinical practice for treating patients with several types of advanced cancer, including renal cell carcinoma (RCC). However, activation of the immune system against cancer cells by the use of ICIs could result in the induction of allograft rejection in organ transplant patients, and to date, the safety of treatment for organ transplant patients with ICIs has not been well-investigated. Here, we report a case of renal allograft rejection in a kidney transplant recipient with metastatic RCC (mRCC) after the administration of nivolumab. Four weeks after initiating treatment with nivolumab, the renal function, in this case, was markedly impaired, and pathological findings of renal biopsy specimens showed acute rejection characterized by marked infiltration of inflammatory cells. Steroid pulse therapy was performed in this case, and despite the lack of improvement in the renal function, his graft was salvaged. Collectively, these findings suggest that it is necessary to pay special attention to the potential for allograft rejection when introducing ICIs for solid organ transplant recipients.