A Case Series of Elevated Donor-Derived Cell-Free DNA Leading to Diagnosis of Posttransplant Glomerulonephritis.

No prior associations between elevated donor-derived cell-free DNA (dd-cfDNA) levels and glomerulonephritis in kidney transplant recipients have been reported. We present 3 cases of posttransplant glomerulonephritis diagnosed in patients by allograft biopsy performed due to elevated dd-cfDNA who maintained baseline serum creatinine and showed no significant change in urinalysis parameters. Case 1 showed C3 glomerulopathy likely related to monoclonal gammopathy in a patient whose native kidney disease was biopsy-proven focal segmental glomerulosclerosis; case 2 showed membranoproliferative glomerulonephritis likely associated with untreated prostate adenocarcinoma in a patient whose native kidney disease was autosomal dominant polycystic kidney disease; and case 3 showed recurrent IgA nephropathy. There was no evidence of rejection in any of the cases, and all patients had improvement in dd-cfDNA levels with treatment of the underlying/associated conditions. These cases highlight the utility of dd-cfDNA obtained during routine transplant monitoring in detecting allograft injury that is not related to rejection.