Immune checkpoint inhibitor–associated renal amyloid A amyloidosis: A case series and review of the literature

Immune checkpoint inhibitors are a cornerstone in the management of many oncological disorders, and their indications continue to grow. However, as with any therapy we must remain vigilant of the possible adverse effects. Although interstitial nephritis is a reported cause of immune checkpoint inhibitor–related kidney injury, immune-mediated glomerular disease has rarely been described. Here, we present three patients being treated with checkpoint inhibitors for colon cancer, metastatic squamous cell carcinoma of the lung, and melanoma, who developed biopsy-proven amyloid A amyloidosis. In all three cases, the malignancies were in remission, yet continued inflammation and amyloid deposition occurred, pointing toward a primary role of the immune checkpoint inhibitor. Treatment generally remains a challenge due to a paucity of reported cases, thus further study of cytokine profile is prudent. In one case, the patient was given tocilizumab in the setting of elevated interleukin-6 levels; unfortunately no appreciable renal benefit was noted and the patient became dialysis dependent. In the other two cases, the patients were treated with colchicine and steroids. One patient had a substantial decrease in proteinuria and inflammatory markers while no significant response was noted in the other. Knowledge of immune checkpoint inhibitor–associated amyloid A amyloidosis is important for the oncologist and the nephrologists.