High urinary interleukin-2 in late post-transplant period portends a risk of decline in kidney allograft function: a preliminary study.

BACKGROUND: Predictive factors for the rate of decline in kidney allograft function beyond the first post-transplant year have not been thoroughly studied. We aimed to determine whether a single measurement of serum and urinary interleukin 2, interleukin 8 and interleukin 10 at 1-15 years after kidney transplantation could predict a decline in estimated glomerular filtration rate (eGFR) over a 2-year period. RESULTS: Greater serum concentrations of interleukin 8 and interleukin 10 in 30 recipients of kidney allograft at enrollment were associated with lower eGFR after 1 year (beta = - 0.616, p = 0.002 and beta = - 0.393, p = 0.035, respectively), whereas serum concentrations of interleukin 8 also demonstrated significant association with eGFR after 2 years of follow-up (beta = - 0.594, p = 0.003). Higher urinary interleukin 2 concentrations were associated with lower eGFR at baseline (rho = - 0.368, p = 0.049) and after the first (beta = - 0.481, p = 0.008) and the second year (beta = - 0.502, p = 0.006) of follow-up. Higher urinary interleukin 2 concentrations predicted certain decline in eGFR of ≥ 25% from baseline after 1 year of follow-up in logistic regression: odds ratio = 2.94, confidence interval 1.06-8.18, p = 0.038. When combined with time after transplantation, urinary interleukin 2 demonstrated good accuracy in predicting rapid decline in eGFR by > -5 mL/min/1.73 m2/year (area under the receiver-operator characteristic curve: 0.855, confidence interval 0.687-1.000, and p = 0.008). CONCLUSIONS: Our findings suggest that urinary interleukin 2 in the late period after kidney transplantation has promise in identifying patients who are at risk for progressive loss of graft function in a short-time perspective and need closer monitoring.

High Serum Level of ß2-Microglobulin in Late Posttransplant Period Predicts Subsequent Decline in Kidney Allograft Function: A Preliminary Study.

BACKGROUND: Identification of patients at risk for kidney allograft (KAG) failure beyond the first posttransplant year is an unmet need. We aimed to determine whether serum beta-2-microglobulin (ß2MG) in the late posttransplant period could predict a decline in KAG function. METHODS: We assessed a value of single measurement of serum ß2MG at one to seventeen years after transplantation in predicting the estimated glomerular filtration rate (eGFR) and the decline in eGFR over a period of two years in 79 recipients of KAG. RESULTS: At baseline serum ß2MG concentration was higher (P = 0.011) in patients with allograft dysfunction: 8.67 ± 2.48 µg/mL versus those with satisfactory graft function: 6.67 ± 2.13 µg/mL. Higher ß2MG independently predicted the lower eGFR, the drop in eGFR by ≥25% after one and two years, and the value of negative eGFR slope. When combined with proteinuria and acute rejection, serum ß2MG had excellent power in predicting certain drop in eGFR after one year (AUC = 0.910). In conjunction with posttransplant time serum ß2MG had good accuracy in predicting certain eGFR drop after two years (AUC = 0.821). CONCLUSIONS: Elevated serum ß2MG in the late posttransplant period is useful in identifying patients at risk for rapid loss of graft function.