Effect of acute rejection episodes on long-term renal graft survival

Blood biomarkers of kidney transplant rejection, an endless search?

INTRODUCTION

The tailoring of immunosuppressive treatment is recognized as a promising strategy to improve long-term kidney graft outcome. To guide the standard care of transplant recipients, physicians need objective biomarkers that can identify an ongoing pathology with the graft or low intensity signals that will be later evolved to accelerated transplant rejection. The early identification of 'high-risk /low-risk' patients enables the adjustment of standard of caring, including managing the frequency of clinical visits and the immunosuppression dosing. Given their ease of availability and the compatibility with a large technical array, blood-based biomarkers have been widely scrutinized for use as potential predictive and diagnostic biomarkers. Areas covered: Here, the authors report on non-invasive biomarkers, such as modification of immune cell subsets and mRNA and miRNA profiles, identified in the blood of kidney transplant recipients collected before or after transplantation. Expert commentary: Combined with functional tests, the identification of biomarkers will improve our understanding of pathological processes and will contribute to a global improvement in clinical management.

The impact of acute rejection in kidney transplantation on long-term allograft and patient outcome

BACKGROUND

Patients with end stage renal disease (ESRD) can be sustained with dialysis therapy.

OBJECTIVES

In this study, we followed up the effect of early acute and late acute rejections on survival rates of patients' grafts.

PATIENTS AND METHODS

We investigated the timing and frequency of acute rejection episodes related to long-term patient-graft survival in Taleghani hospital between 1990 and 2011. Recipients were divided into three groups as Group-1 (no rejection), Group-2 (early acute rejection [EAR]: less than 3-months) and Group-3 (late acute rejection [LAR]: after 3 months of transplant).

RESULTS

One and five-year patient's survival rates were 94.87% and 93.8%, and graft survival (GS) rates were 92.6% and 81.9%. EAR and LAR occurred in 125 (18.8%) and 77 (11.7%) patients, respectively. Graft and patient survival rates at one and five years were as follows; Group-1 (Graft 96.7% and 94.5% patient: 97.4% and 96.8%), Group-2 (Graft: 72% and 61%, patient: 85.6% and 84%), Group-3 (Graft: 84.4% and 36.8%, patient: 92.2% and 89.4%). Recipient age, type and length of dialysis, number of transplantations and the status of panel reactivity antibody (PRA) had no effect on the type of rejection. LAR was more commonly associated with males (P = 0.001) and donors' age was associated with rejection (P = 0.0002). Five-year GS rate among the three groups was lower in the LAR group (P < 0.0001).

CONCLUSIONS

LAR had a negative impact on long-term renal allograft survival and the risk of chronic graft dysfunction increased in patients with a history of LAR.

Characteristics of long-term live-donor renal allograft survivors

BACKGROUND/AIMS

Despite the high rate of rejection, allograft failure and patient mortality in the early years of renal allotransplantation, some patients have done-remarkably well. We report here on 62 renal transplant recipients out of 144 patients (43%) who had functioning grafts for more than 15 years (range 15-24 years).

MATERIALS

Demographic and follow-up data for patients fulfilling the criteria were reviewed. These patients include 43 males and 19 females, with a mean age at transplantation of 27.5 +/- 6.6 years (range 9-43 years), and mean donor age of 30 +/- 8.6 years. The donor source was 8 parents, 49 siblings and 5 unrelated. The main causes of end-stage renal disease were chronic pyelonephritis and chronic glomerulonephritis. Twenty-nine patients were treated with cyclosporine (CsA) while 33 patients were primarily immunosuppressed by steroids and azathioprine.

RESULTS

Acute rejection episodes occurred in 40 patients (64.3%), out of them 19 patients experienced two or more acute rejection episodes. Univariate analysis showed that recipient and donor age, HLA-DR matching, pre- and post-transplant hypertension, ATN, delayed diuresis and chronic allograft nephropathy are significant risk factors; while recipient age, delayed diuresis and post-transplant hypertension were still significant by multivariate analysis.

CONCLUSIONS

We concluded that renal transplantation, even in its earliest years and despite the numerous complications, has provided 15 or more years of near-normal life to patients with end-stage renal disease. Certain characteristics of long-term renal allograft survivors include young donor/recipient pairs, good DR matching with less pre- and post-transplantation prevalence of hypertension.

Chrono and clinical pharmacokinetic study of tacrolimus in continuous intravenous administration

BACKGROUND

The circadian variation of clinical pharmacokinetics of tacrolimus in kidney transplant recipients receiving continuous intravenous administration has not been clarified. The aim of this study was to evaluate the circadian variation of this drug in continuous intravenous administration, with regard to the dosing scheme for conversion from intravenous to oral therapy.

METHODS

The blood concentration-time curve was studied in 10 living-related kidney transplant recipients, aged 18-51 years (mean, 36.5 years), 1 day before operation for preoperative oral administration, the third postoperative day for continuous intravenous administration and the sixth postoperative day at the conversion from intravenous to oral therapy.

RESULTS

Although the total body clearance of daytime was slightly higher than that of night-time, the intravenous tacrolimus infusion maintained an adequate therapeutic blood concentration for 24 h. There were significant differences between the preoperative and the postoperative state in the area under the curve, total body clearance and bioavailability for the oral administration. The mean absolute bioavailability was 17.7% in preoperative and 11.1% in postoperative state, respectively and a large interindividual variation was confirmed in this parameter, which was 7.0-27.2% for preoperative and 6.4-22.0% for postoperative area under the curve, respectively.

CONCLUSION

This study proposes that intravenous administration is a safe and appropriate method to achieve the required blood concentration in patients with various tacrolimus metabolism in the early post-transplant period. As the oral tacrolimus absorption was found to be variable between preoperative and postoperative states in identical patients, the conversion dosage cannot be calculated from preoperative oral or postoperative intravenous pharmacokinetics. Frequent blood concentration monitoring is needed to ensure safe treatment.