Race and delayed kidney allograft function

HLA-A amino acid polymorphism and delayed kidney allograft function

Delayed allograft function (DGF) is a common adverse event in postrenal transplantation. The etiology of DGF is thought to include both nonimmunologic (donor age, cold ischemia time, and recipient race) and immunologic factors. We examined the association of DGF with amino acid mismatches at 66 variable sites of the HLA-A molecule in a prospective cohort study of 697 renal transplant recipients of deceased donors. Using a multivariate logistic regression model adjusted for nonimmunologic risk factors, we show that combinations of a few amino acid mismatches at crucial sites of HLA-A molecules were associated with DGF. In Caucasian recipients, a mismatch at position 62, 95, or 163, all known to be functionally important within the antigen recognition site, was associated with an increased risk for DGF. Furthermore, a decreased risk for DGF was associated with a mismatch at HLA-A family-specific sites (149, 184, 193, or 246), indicating that evolutionary features of HLA-A polymorphism separating HLA-A families and lineages among donor-recipient pairs may correlate with the magnitude of alloreactivity influencing the development of DGF. These findings suggest that amino acid polymorphisms at functionally important positions at the antigen recognition site of the HLA-A molecule have a significant influence on DGF.

Effect of a novel inducible nitric oxide synthase inhibitor, FR260330, in prevention of renal ischemia/reperfusion injury in vervet monkeys

Cytotoxic nitric oxide (NO) is produced during ischemia/reperfusion (I/R) injury by the expression of inducible NO synthase (iNOS). Therefore, continuous iNOS inhibition might prevent early graft dysfunction. FR260330, a potent and selective inhibitor of iNOS activity, impedes the dimmerization of iNOS monomer. In this study, the effect of FR260330 in the prevention of renal I/R injury was evaluated in the model of one kidney ischemia in Vervet monkeys. A total of 18 male Vervet monkeys were randomly assigned to two equal groups (n=9). Transient (60 min) left renal ischemia was produced by simultaneous contralateral nephrectomy in treated (FR260330 20 mg/kg/day) and placebo control groups. Renal function and other biochemical parameters as well as FR260330 concentrations were studies until day 15 after I/R injury. All monkeys survived after 60 min I/R injury until sacrifice on day 15. Serum creatinine in the untreated controls increased significantly in comparison to the FR260330-treated group on days 2, 3, 4, and 7 (P<0.05). Plasma FR260330 concentration after oral administration showed that C(max) was 3.251+/-2.526 microg/ml, and T(max) was 4 hr. This study thus finds that FR260330, as a selective iNOS inhibitor, effectively prevents renal I/R injury in Vervet monkeys.

Prediction of delayed renal allograft function using an artificial neural network

BACKGROUND

Delayed graft function (DGF) is one of the most important complications in the post-transplant period, having an adverse effect on both the immediate and long-term graft survival. In this study, an artificial neural network was used to predict the occurrence of DGF and compared with traditional logistical regression models for prediction of DGF.

METHODS

A total of 304 cadaveric renal transplants performed at the Jewish Hospital, Louisville were included in the study. Covariate analysis by artificial neural networks and traditional logistical regression were done to predict the occurrence of DGF.

RESULTS

The incidence of DGF in this study was 38%. Logistic regression analysis was more sensitive to prediction of no DGF (91 vs 70%), while the neural network was more sensitive to prediction of yes for DGF (56 vs 37%). Overall prediction accuracy for both logistic regression and the neural network was 64 and 63%, respectively. Logistic regression was 36.5% sensitive and 90.7% specific. The neural network was 63.5% sensitive and 64.8% specific. The only covariate with a P < 0.001 was the transplant of a white donor kidney to a black recipient. Cox proportional hazard regression was used to test for the negative effect of DGF on long-term graft survival. One year graft survival in patients without DGF was 92 +/- 2% vs 81 +/- 3% in patients with DGF. The 5-year graft survival was not affected by DGF in this study.

CONCLUSION

Artificial neural networks may be used for prediction of DGF in cadaveric renal transplants. This method is more sensitive but less specific than logistic regression methods.

A prospective, randomized, clinical trial of intraoperative versus postoperative Thymoglobulin in adult cadaveric renal transplant recipients

BACKGROUND

Delayed graft function (DGF) is frequently observed in recipients of cadaveric renal transplants. Previous retrospective or nonrandomized studies have suggested that intraoperative administration of polyclonal antithymocyte preparations may reduce the incidence of DGF, possibly by decreasing ischemia-reperfusion injury.

METHODS

We performed a prospective randomized study of Thymoglobulin induction therapy in adult cadaveric renal transplant recipients. Between January 2001 and January 2002, 58 adult cadaveric renal transplant recipients were randomized to receive intraoperative or postoperative Thymoglobulin induction therapy. Three to six doses of Thymoglobulin (1 mg/kg/dose) were administered during the first week posttransplant. Baseline immunosuppression consisted of tacrolimus (54 of 58) or cyclosporine A (4 of 58), steroids, and mycophenolate mofetil. DGF was defined by the requirement for hemodialysis within the first week posttransplant.

RESULTS

There were no significant differences between the two groups in recipient demographics, donor age, cold ischemia time, or total number of doses of Thymoglobulin administered. Intraoperative Thymoglobulin administration was associated with significantly less DGF and a lower mean serum creatinine on postoperative days 10 and 14 (P<0.05). Posttransplant length of stay was also significantly shorter for the intraoperative Thymoglobulin patient group. The acute rejection rate was also lower in the intraoperative treatment group but this did not achieve statistical significance. There was no difference in the incidence of cytomegalovirus disease between the two groups.

CONCLUSIONS

The results of this study indicate that intraoperative Thymoglobulin administration, in adult cadaveric renal transplant recipients, is associated with a significant decrease in DGF, better early allograft function in the first month posttransplant, and a decreased posttransplant hospital length of stay.

Effect of the use or nonuse of long-term dialysis on the subsequent survival of renal transplants from living donors

BACKGROUND

The effect on allograft survival of the transplantation of kidneys from living donors without the previous initiation of long-term dialysis is controversial.

METHODS

Using data from the U.S. Renal Data System, we performed a retrospective cohort study of 8481 patients who were or who were not treated by long-term dialysis before receiving a kidney transplant from a living donor. The relative rate of allograft failure for patients who received a transplant without previously undergoing long-term dialysis, as compared with patients who underwent long-term dialysis before transplantation, was assessed by proportional-hazards analysis, with adjustment for potential confounding variables, including the transplantation center and median household income. The association between the receipt of a kidney transplant from a living donor without previous dialysis ("preemptive transplantation") and the risk of biopsy-confirmed acute rejection within six months after transplantation was evaluated by conditional logistic-regression analysis, with adjustment for the transplantation center.

RESULTS

Transplantation of a kidney from a living donor without previous long-term dialysis was associated with a 52 percent reduction in the risk of allograft failure during the first year after transplantation (rate ratio, 0.48; P=0.002), an 82 percent reduction during the second year (rate ratio, 0.18; P=0.001), and an 86 percent reduction during subsequent years (rate ratio, 0.14; P=0.001), as compared with transplantation after dialysis. The reduction in the rate of allograft failure during the first year was attenuated when adjustment was made for the timing of acute rejection within the first year (rate ratio, 0.69; 95 percent confidence interval, 0.44 to 1.10; P=0.10). Increasing duration of dialysis was associated with increasing odds of rejection within six months after transplantation (P=0.001).

CONCLUSIONS

Preemptive transplantation of kidneys from living donors without the previous initiation of dialysis is associated with longer allograft survival than transplantation performed after the initiation of dialysis.

Increased levels of GALbeta1-4GLCNACalpha2-6 sialyltransferase pretransplant predict delayed graft function in kidney transplant recipients

BACKGROUND

Galbeta1-4GlcNAcalpha2-6 sialyltransferase (ST6GalI) is an acute phase reactant whose release from cells can be induced by proinflammatory cytokines. Because patients with chronic renal failure have high circulating levels of proinflammatory cytokines, we hypothesized that patients on the renal transplant waiting list would have high circulating levels of ST6GalI, which might adversely affect post-transplant events.

METHODS

Levels of ST6GalI were measured in the serum of 70 patients immediately before renal transplant; these were correlated with posttransplant events, such as delayed graft function and rejection.

RESULTS

The mean serum level of ST6GalI was significantly higher in the patients (3162+/-97 U) than in 19 controls (2569 +/- 125 U; P<0.003). Patients who required dialysis posttransplant for treatment of delayed graft function (n=20) had significantly higher levels of ST6GalI pretransplant (3735+/-228 U) than patients (n=50) who did not require dialysis (2933+/-83 U; P<0.0001). In a multivariate analysis the ST6GalI level and cold ischemic time were found to be independent risk factors for the development of delayed graft function.

CONCLUSIONS

ST6GalI levels are high in renal failure patients awaiting a renal transplant and may be a risk factor for the development of delayed graft function. The assessment and perhaps modulation of a potential transplant recipient's ST6GalI systemic level may be beneficial.