Proximal tubular dysfunction is associated with chronic allograft nephropathy and decreased long-term renal-graft survival.
BACKGROUND
Chronic allograft nephropathy is the major cause of graft loss after the first year of transplantation. Although many conditions are associated with its development, there is no method that can anticipate its risk in patients with good renal function.


METHODS
We prospectively studied 92 renal-transplant recipients with good and stable allograft function and correlated the development of chronic allograft nephropathy and graft loss with their levels of urinary retinol binding protein (uRBP). Patients were divided in two groups regarding the level of their tubular protein: high, above 0.400 mg/L, and normal levels, 0.400 mg/L or less.


RESULTS
Forty-eight (52%) patients had high levels of uRBP. At the enrollment time, patients with high and normal uRBP had comparable serum creatinine and cyclosporine trough levels. During a 5-year follow-up period, chronic allograft nephropathy was detected in 23 (25%) patients, 19 (82.6%) of whom had high levels of uRBP. Five-year chronic allograft nephropathy-free and graft survivals were significantly worse in patients with higher levels of uRBP than in patients with normal levels (57.5% vs. 89.9% P=0.0004; 70.7% vs. 100%, respectively, P=0.0002). High levels of uRBP were the strongest factor associated with the development of chronic allograft nephropathy (RR=5.3, 95% confidence interval 1.45-19.58, P=0.012).


CONCLUSIONS
Among renal-transplant patients with good and stable graft function, high levels of uRBP identify those having a high risk of developing chronic allograft nephropathy.
Division of Nephrology, Universidade Federal de São Paulo, Rua Botucatu 740, 04023-900 São Paulo, Brazil.
Niels O S
NO
Câmara
Marcelo S
MS
Silva
Sônia
S
Nishida
Aparecido B
AB
Pereira
Alvaro
A
Pacheco-Silva
D000293:Adolescent; D000328:Adult; D001938:Brazil; D002648:Child; D002675:Child, Preschool; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology; D006085:Graft Survival / Q000502:physiology*; D006650:Histocompatibility Testing; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000473:pathology*; D016031:Liver Transplantation / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D014184:Transplantation, Homologous / Q000473:pathology