Immune checkpoint inhibitor therapy-associated graft intolerance syndrome in a failed kidney transplant recipient

Immune checkpoint inhibitors (ICPIs) are monoclonal antibodies against inhibitory receptors on T cells resulting in anticancer activity. In kidney transplant (KT) recipients, ICPI use has been associated with acute allograft rejection. In failed allografts, however, the effects of ICPIs are unknown. We present a case of a 66-year-old man with a history of diabetes, renal cell cancer, left native nephrectomy, and end-stage kidney disease. He received a deceased donor KT which failed after 6 years due to biopsy-proven recurrent diabetic nephrosclerosis. He was started on hemodialysis and his immunosuppression was gradually weaned off. A year later, he was diagnosed with renal cell cancer in his right native kidney requiring nephrectomy. He later developed metastasis and was started on combination ICPIs. He developed hematuria, allograft pain, and malaise consistent with graft intolerance syndrome 28 days after starting ICPIs. Urine culture and cystoscopy were normal. A computed tomography scan of his abdomen revealed an enlarged allograft with patchy enhancement. After a multidisciplinary discussion, he underwent transplant nephrectomy. Histopathology showed chronic active T cell-mediated rejection. As ICPI use becomes prevalent, practitioners need to be aware of its potential complications among KT recipients both with functioning and failed allografts.