Rapid resolution of proteinuria of native kidney origin following live donor renal transplantation

To assess the contribution of the protein content of urine from the native kidneys to post-transplant proteinuria, we prospectively studied 14 live donor transplant recipients with a pre-transplant random urine protein to creatinine ratio (UPr:Cr) >0.5. Seven patients received preemptive transplants, and seven patients were on dialysis pre-transplant (with residual urine output). Resolution of proteinuria was defined as UPr:Cr < 0.2. Immunosuppression consisted of tacrolimus, mycophenolate mofetil and corticosteroids. Anti-hypertensive drugs that might reduce proteinuria were avoided during the study. The serum creatinine was 8.7 +/- 0.7 mg/dL pre-transplant, and the nadir post-transplant serum creatinine was 1.4 +/- 0.1 mg/dL. The pre-transplant UPr:Cr ranged between 0.5 and 9.2 (mean = 2.9 +/- 0.6). The UPr:Cr decreased to < 0.2 in all 14 patients at a mean of 4.5 weeks post-transplant (range 1-10 weeks). In conclusion, in live donor renal transplant recipients with immediate graft function, proteinuria of native kidney origin resolves in the early post-transplant period. After the immediate post-transplant period, proteinuria cannot be attributed to the native kidneys, and work up for proteinuria should focus on the allograft.