Protocol biopsies after kidney transplantation

Non-traditional risk factors of progression of chronic kidney disease in adult population: a scoping review

Chronic kidney disease (CKD) has become a public health concern over the last several years. Nowadays developed countries spend around 3% of their annual health-care budget on patients with CKD. According to the scientific community the most remarkable risk factors for CKD are diabetes and hypertension. Unknown CKD etiology has been reported as a global phenomenon including uncommon risk factors such as: dehydration, leptospirosis, heat stress, water quality, and others. This study aims to report non-traditional risk factors for ESRD based on a scoping review methodology. The scoping review methodology described by Arksey and O'Malley was used by performing an extensive review of the information. A total of 46 manuscripts were reviewed. The non-traditional ESRD risk factors are depicted based on six categories. Gender and ethnicity have been considered as risk factors for ESRD. Erythematous systemic lupus (ESL) is reported as an important risk factor for ESRD. Pesticide use has been an significant risk factor due to its effects on human and environmental health. Some compounds commonly used in homes against insects and plants are related to ESRD. Congenital and hereditary diseases in the urinary tract have been studied as a cause of ESRD in children and young adults. End-stage renal disease is a major concern for public health on a global level. As it can be seen, non-traditional risk factors are several and have different etiologies. It is necessary to put the issue on the table and add it to the public agenda in order to find multidisciplinary solutions.

Predicting Fibrosis Progression in Renal Transplant Recipients Using Laser-Based Infrared Spectroscopic Imaging

Renal transplants have not seen a significant improvement in their 10-year graft life. Chronic damage accumulation often leads to interstitial fibrosis and tubular atrophy (IF/TA) and thus graft function loss over time. For this reason, IF/TA has been the chief suspect for a potential prognostic marker for long term outcomes. In this study, we have used infrared spectroscopic (IR) imaging to interrogate the biochemistry of regions of fibrosis from renal transplant biopsies to identify a biochemical signature that can predict rapid progression of fibrosis. IR imaging represents an approach that permits label-free biochemical imaging of human tissues towards identifying novel biomarkers for disease diagnosis or prognosis. Two cohorts were identified as progressors (n = 5, > 50% fibrosis increase between time points) and non-progressors (n = 5, < 5% increase between time points). Each patient had an early time point and late time point biopsy. Collagen associated carbohydrate moieties (ν(C–O), 1035 cm⁻¹ and ν(C–O–C),1079 cm⁻¹) spectral ratios demonstrated good separation between the two cohorts (p = 0.001). This was true for late and early time point biopsies suggesting the regions of fibrosis are biochemically altered in cases undergoing progressive fibrosis. Thus, IR imaging can potentially predict rapid progression of fibrosis using histologically normal early time point biopsies.

A comparison of three induction therapies on patients with delayed graft function after kidney transplantation

We compare the outcomes of induction therapies with either methylprednisolone (group 1, n = 58), basiliximab (group 2, n = 56) or alemtuzumab (group 3, n = 98) in primary deceased donor kidney transplants with delayed graft function (DGF). Protocol biopsies were performed. Maintenance was tacrolimus and mycophenolate with steroid (group 1 and 2) or without steroid (group 3). One-year biopsy-confirmed acute rejection (AR) rates were 27.6, 19.6 and 10.2 % in group 1, 2 and 3 (p = 0.007). AR was significantly lower in group 3 (p = 0.002) and group 2 (p = 0.03) than in group 1. One-year graft survival rates were 90, 96 and 100 % in group 1, 2 and 3 (log rank p = 0.006). Group 1 had inferior graft survival than group 2 (p = 0.03) and group 3 (p = 0.002). The patient survival rates were not different (96.6, 98.2 and 100 %, log rank p = 0.81). Multivariable analysis using methylprednisolone induction as control indicated that alemtuzumab (OR 0.31, 95 % CI 0.11-0.82; p = 0.03) and basiliximab (OR 0.60, 95 % CI 0.23-0.98; p = 0.018) were associated with lower risk of AR. Therefore, alemtuzumab or basiliximab induction decreases AR and improves graft survival than methylprednisolone alone in patients with DGF. Alemtuzumab induction might also allow patients with DGF to be maintained with contemporary steroid-withdrawal protocol.

Clinical approach to kidney disease in kidney recipients in Spain

BACKGROUND AND OBJECTIVES

In the present study, clinical criteria used by Spanish nephrologists when approaching chronic kidney disease (CKD) in kidney recipients, as well as their level of maintenance and control of renal function, were evaluated.

METHODS

An epidemiological, observational, multicenter, nation-wide, prospective study was carried out, with a 6-month follow-up period. Three hundred and sixty-eight adult patients with stage3 kidney disease after a 24-month or longer post-transplantation follow-up period were included. Visits schedule included a retrospective visit, a baseline visit, an optional mid-term visit, and a final visit at month6.

RESULTS

Mean time since kidney transplantation was 8.2±5.4years. Most common pre-transplant cardiovascular risk factors were high blood pressure (80.2%), followed by high cholesterol levels (61.7%). Serum creatinine levels showed a statistically significant decrease from baseline visit to 6-month visit (0.06±0.22; P<.0001), and glomerular filtration rate (GFR) reduction was -1.03±6.14 (P=0.0014). Significant independent prognostic factors for GFR worsening were: higher 24-hour proteinuria (OR=1.001 per mg; P=.020), longer time since transplantation (OR=1.009 per month; P=.017), and lower hemoglobin levels (OR=1.261 per g/dl; P=.038). Donor age also had some negative influence (OR=1.021 per year; P=.106). Biopsies were obtained in only 8% of kidney transplant recipients with stage 3 CKD with an intervention being carried out in 25.4% of cases.

CONCLUSIONS

Secondary markers and factors resulting in CKD progression, particularly anemia, are still frequently uncontrolled after kidney transplantation. Only about 2% of patients benefit from a therapeutic intervention based on a biopsy. Clinical perception differs from objective measures, which results in an obvious clinical inertia regarding risk factor control in such patients.

Biological pathways and potential targets for prevention and therapy of chronic allograft nephropathy

Renal transplantation (RT) is the best option for patients with end-stage renal disease, but the half-life is limited to a decade due to progressive deterioration of renal function and transplant failure from chronic allograft nephropathy (CAN), which is the leading cause of transplant loss. Extensive research has been done to understand the pathogenesis, the biological pathways of fibrogenesis, and potential therapeutic targets for the prevention and treatment of CAN. Despite the advancements in the immunosuppressive agents and patient care, CAN continues to remain an unresolved problem in renal transplantation. The aim of this paper is to undertake a comprehensive review of the literature on the pathogenesis, biological pathways of RT fibrogenesis, and potential therapeutic targets for the prevention and therapy of CAN.

The cutting (w)edge--comparative evaluation of renal baseline biopsies obtained by two different methods

BACKGROUND

The assessment of donor-derived damage of transplanted kidneys might be instrumental for estimating donor organ quality and for predicting short- and long-term organ outcome. In the present study, we report a new standardized method for obtaining pre-transplant kidney biopsy specimens. Instead of taking wedge biopsies (WBs), a skin punch biopsy (PB) tool was utilized to obtain standardized biopsy samples that also represented deeper cortical zones.

METHODS

We compared 147 PB specimens and 114 WBs with respect to the number of glomeruli and arterial vessels they contained. The performance of the two biopsy methods in detecting glomerular damage, interstitial fibrosis/tubular atrophy (IF/TA) and arteriosclerosis was determined by evaluation of subsequent transplant core biopsies of the patients. Statistical comparison employed Kruskal-Wallis and kappa (κ) tests.

RESULTS

Significantly more PB samples (89%) than WBs (66%) were diagnostically adequate according to the Banff criteria. Despite a higher number of glomeruli in WBs (34.6 versus 21.7 in punch biopsies), arteries were present in only 68% of WBs but could be found in 93% of punch biopsies. The comparison of findings in pre-transplant biopsies with lesions in corresponding post-transplant core biopsies revealed a superior diagnostic concordance for IF/TA and arteriosclerosis for punch biopsies than for WBs, reaching kappa values of 0.823 versus 0.729 and 0.661 versus 0.516, respectively.

CONCLUSION

The use of skin PB tools for obtaining baseline biopsies from transplanted kidneys is a safe and effective method for assessment of donor-derived damage of the organ.

Impact of early kidney resistance index on kidney graft and patient survival during a 5-year follow-up

BACKGROUND

Resistance index (RI) measured by Doppler sonography during the early post-transplant period reflects interstitial oedema within the transplanted kidney. We have prospectively analysed the relationship between RI measured shortly after kidney transplantation (KTx), patient and graft survival, as well as kidney graft function during a 5-year follow-up.

METHODS

RI was measured at the second to fourth day after KTx in 364 consecutive patients, who were divided into tertiles, according to baseline RI value (Group 1: RI < 0.73, Group 2: RI between 0.73 and 0.85 and Group 3: RI > 0.85). The kidney graft function [estimated glomerular filtration rate (eGFR)] during the follow-up period was calculated according to the Modification of Diet in Renal Disease formula.

RESULTS

During the 5-year follow-up period, 23 patients died (2.6 versus 6.5 versus 9.6% in RI tertiles, respectively) and 59 lost their kidney graft (12.1 versus 17.7 versus 18.4%, respectively). Survival analyses showed that the effect of RI was significant for a combined outcome [graft loss or death; hazard ratio (HR) = 10.88] and in relation to death, it was of borderline significance (HR = 45.3, P = 0.09). The effect of delayed graft function (DGF) was only significant on graft loss (HR = 1.73). eGFR in the highest tertile was lower than in the lowest tertile during the entire follow-up period.

CONCLUSIONS

High RI values measured in segmental arteries in the very early post-transplant period predict worse kidney graft function and increased risk of all-cause graft loss, including patient death in the 5-year follow-up period. (ii) The predictive value of RI is not completely independent from the adverse influence of DGF on the premature graft loss.

Treatment of subclinical injuries detected by protocol biopsy improves the long-term kidney allograft function: a single center prospective randomized clinical trial

BACKGROUND

The long-term benefit of early treatment of subclinical disorders detected in kidney allografts by protocol biopsy is controversial. We collected 145 protocol biopsies from 113 recipients for comparison with 51 control patients in a single-center, prospective, randomized trial.

METHODS

Ultrasound-guided biopsies were performed in recipients with stable renal function. Samples were taken at 3 (n=66) and/or 12 months (n=79) after transplantation. The biopsies were evaluated according to the Banff scheme, and patients were treated based on the diagnosis. Changes in glomerular filtration rate (GFR) were compared with 51 patients who were randomized as a control group.

RESULTS

The findings on 38 samples (29%) were considered to be normal. Based on the pathology findings, such as subclinical acute rejection (n=23), calcineurin inhibitor toxicity (n=28), chronic rejection (n=6), and other specific pathologies (n=23), including polyoma virus nephropathy (n=2), induced treatment among 82 recipients (57%). Significantly better graft function was observed at 3-year follow-up among the biopsy group, compared with controls: GFR = 46.0 ± 13.8 vs 35 ± 15 mL/min (P=.002). The 5-year graft survival was significantly higher in the biopsy (81%) than in the control (55.6%) group (P=.0012).

CONCLUSION

Early detection and treatment of subclinical pathologies improved graft function and long-term survival. Protocol biopsies were a valuable tool for posttransplantation management.

Intensivtherapie nach Transplantation solider Organe

Der Intensivmedizin kommt eine zentrale Bedeutung in Rahmen der Transplantationsmedizin zu. Aufgrund ihrer marginalen Organfunktion benötigen die Patienten nicht selten bereits im Vorfeld der Transplantation eine intensivmedizinische Versorgung, zu der dann auch die Evaluation und Listung sowie die Koordination des zeitkritischen Transplantationsablaufs gehören können. Die direkte postoperative Betreuung nach komplexen Organtransplantationen bedarf fast ausschließlich der Versorgung im Rahmen von Überwachungsstationen, in denen sowohl direkt transplantationsassoziierte Komplikationen als auch Nebenerkrankungen eine intensivmedizinische Behandlungen notwendig machen. Sie zielt auf die Stabilisierung der Organfunktion, Behandlung begleitender Organdysfunktionen, adäquate Induktion der Immunsuppression und die möglichst frühe Wiedererlangung der Eigenständigkeit des Transplantierten ab.

[Intensive therapy after solid organ transplantation]

Transplantation medicine is an interdisciplinary task and the priority objective is a fast recovery to patient independence. After kidney transplantation the crucial aims are monitoring of transplant perfusion, maintainance of an adequate volume status and avoidance of nephrotoxic medications. Transplantation for patients with advanced chronic liver failure has become more common since the implementation of the model of end stage liver disease (MELD) allocation system which is associated with more complicated proceedings. The essentials of critical care after liver transplantation are monitoring of transplant function, diagnosis of perfusion or biliary tract problems, specific substitution of coagulation factors and hemodynamic optimation due to avoidance of hepatic congestion. Many patients listed for heart transplantation need preoperative intensive care due to impaired heart function. Postoperatively a specific cardiac support with pulmonary arterial dilatators and inotropics is usually necessary. Lung transplantation aims at an improvement of patient quality of life. Postoperative critical care should provide a limitation of the pulmonary arterial pressure, avoidance of volume overload and rapid weaning from the respirator.

Detecting adaptive immunity: applications in transplantation monitoring

In recent decades, continuous improvements in immunosuppressive therapy have led to a significant increase in kidney allograft survival. Despite innovative developments and improvements in immunosuppression, chronic allograft injury and late graft loss still remain major causes of morbidity and mortality. In clinical practice, long-term immunosuppression is adapted and fine-tuned according to drug levels, kidney function, and biopsy results. As an invasive procedure, indication biopsy still represents an indispensible diagnostic gold standard. However, in an effort to further improve outcomes on the basis of individualized treatment, there is an urgent need for noninvasive assays, as well as biomarkers, to more accurately monitor allogeneic responses and predict the risk of acute and chronic allograft rejection. This article discusses strategies for immune monitoring of T-cell responsiveness and humoral alloreactivity. Furthermore, new microarray and gene profiling data are highlighted, which may identify hyporesponsive transplant recipients who could benefit from a reduction or even withdrawal of immunosuppression. Finally, supplementary transplant risk assessment markers, such as soluble CD30 and urinary effector molecule analysis, are discussed as promising new tools. Recent developments and improvements in test principles to monitor and predict allograft immunity are encouraging and may herald the transition of present empiric immunosuppression to individualized immunosuppressive treatment. Nonetheless, before implementation of immune monitoring in routine clinical practice, there is still a need for prospective trials designed to clarify the actual diagnostic potential of individual test systems in a therapeutic context.

Complications post renal transplantation: literature focus on BK virus nephropathy and diagnostic tools actually available

Clinical diagnosis of kidney transplants related illnesses is not a simple task. Several studies were conducted to define diseases and complications after renal transplantation, but there are no comprehensive guidelines about diagnostic tools for their prevention and detection.

The Authors of this review looked for the medical literature and pertinent publications in particular to understand the role of Human Polyomavirus BK (BKV) in renal failure and to recognize analytical techniques for BK virus associated nephropathy (BKVAN) detection.

Evaluating the accuracy of functional biomarkers for detecting histological changes in chronic allograft nephropathy

The most common cause of late kidney transplant failure is chronic allograft nephropathy (CAN). Much research has focused on identifying biomarkers (or correlates) that would predict subsequent CAN and allow timely intervention. Functional biomarkers such as serum creatinine and estimated glomerular filtration rate (eGFR) have been widely adopted, even though they have not been rigorously evaluated as surrogate markers. This study evaluated serum creatinine and eGFR for predicting the early histopathological changes seen in transplant protocol biopsies (TPB). We prospectively followed 289 kidney transplant patients in the Southern Alberta Transplant Program who had TPB at 6-12 months post-transplant. Tissue samples (n = 280) were independently examined by renal pathologists. The ability of serum creatinine or eGFR to predict the threshold level for abnormal histopathology was evaluated by calculating the area under the receiver operator characteristic curve. Serum creatinine and eGFR had poor predictive value (most confidence intervals included 0.5, indicating no predictive ability) for ten individual histological measurements (Banff 97 scores), and the Chronic Allograft Damage Index. We conclude that serum creatinine and eGFR have a limited clinical role in predicting the early histopathological changes that precede CAN and should not be used for this purpose.

Reticulocytes and their immature fraction do not detect acute rejection after kidney transplantation

BACKGROUND

Early detection of an acute rejection episode is an important problem in monitoring transplant patients. Erythropoietin (EPO) production is diminished in patients suffering from chronic renal insufficiency or acute rejection. Therefore, a decrease of reticulocyte counts and of young reticulocytes might indicate the emergence of an acute rejection episode. This pilot study examined the value of reticulocyte parameters as indicators of acute rejection episodes.

PATIENTS AND METHODS

Reticulocyte parameters were examined in 25 renal transplant patients. Initial immunosuppressants therapy was based on a combination of methylprednisolone, mycophenolatmofetil, cyclosporine and antithymocyte globulin or basiliximab, CellCept, cyclosporine, and ATG or Simulect. During the first 3 weeks after the procedure, blood samples were collected three times per week. Complete blood counts were performed on XE-2100 analyzers (Sysmex). Acute rejection was biopsy-proven.

RESULTS

Acute rejection episodes were not accompanied by significantly altered reticulocyte parameters. During the first weeks, the reticulocyte count or the immature fraction, respectively, did not differ between patients with delayed versus immediate onset of renal function: reticulocyte count 1.70 +/- 1.06% vs 1.58 +/- 1.10% and ratio of immature (high fluorescent) reticulocytes 22.8 +/- 7.9% vs 17.6 +/- 9.4%).

CONCLUSION

Reticulocyte counts and determination of the immature reticulocyte fraction were not significantly altered by an acute rejection episode. Various influences modulate the release of EPO and reaction of erythropoiesis upon an EPO stimulus.

Utility of Biopsy in Kidney Transplants With Delayed Graft Function and Acute Dysfunction

Renal biopsy is currently the gold standard to assess the causes of renal allograft dysfunction. In the present study, we prospectively assessed the role of the renal allograft biopsy in the diagnosis and treatment of renal allograft dysfunction. Seven hundred and fifteen biopsies were performed in 399 patients. The anatomopathological results in group 1 (delayed graft function) were: 60.4% acute tubular necrosis, 17.6% acute rejection, 4.3% calcineurin inhibitor toxicity, and 17.7% other diagnoses; in group 2 (acute graft dysfunction): 42.3% acute rejection, 22% acute tubular necrosis, 8.4% calcineurin inhibitor toxicity, and 27.3% other diagnoses. Among patients with delayed graft function, 42.2% of biopsies led to a change in the treatment. In 60.5%, the biopsy of patients with acute dysfunction led to a change in the patient management. In our series, the result of the biopsy disagreed with the clinical diagnosis in 39.6% and 57.7% of cases, respectively. These results demonstrated that renal graft biopsy remains an indispensable tool for the accurate management of kidney transplant patients.

Histologic and clinical findings in living donor allografts with long-term stable function

BACKGROUND/AIMS

Protocol biopsy is an important strategy which assesses the histological changes that can occur in the renal allograft and adversely affect its outcome. We aimed to evaluate histological changes in long-term living donor transplants.

METHODS

Elective biopsies were done for 120 live donor renal transplant recipients with well-functioning grafts and no rejection history at least 1 year or more after transplant. All patients had serum creatinine levels <2 mg/dl. The histopathological findings using the chronic allograft damage index score were correlated with different clinical and immunological parameters.

RESULTS

Chronic tubulointerstitial fibrosis was the most prevalent finding (85% of cases), mostly of mild degree. Normal biopsies were reported in only 7.5% of cases, whereas chronic cyclosporine nephrotoxicity was detected in 5.8% of biopsies. Posttransplant hypertension was significantly correlated with glomerulosclerosis, and posttransplant diabetes with glomerulosclerosis, mesangial matrix increase, tubular atrophy and interstitial fibrosis. The main risk factors associated with a high chronic allograft damage index score were DR mismatching, posttransplant diabetes and time of biopsy. All histopathological changes increased with advancing donor age and declining graft function.

CONCLUSION

Elective biopsies showed that histopathological findings do exist even with stable renal function that may pave the way for predicting long-term graft outcome.

Association of high pretransplant sIL-6R plasma levels with acute tubular necrosis in kidney graft recipients

BACKGROUND

Delayed graft function is primarily caused by acute tubular necrosis (ATN). We studied in renal transplant recipients with posttransplant graft biopsy whether an up-regulated immune system in the recipient immediately before transplantation affects the risk of developing ATN and might be relevant for the pathogenesis of ATN.

METHODS

In a retrospective study, we analyzed pretransplant and early posttransplant soluble interleukin (sIL)-1RA, interleukin (IL)-2, sIL-2R, IL-3, IL-4, IL-6, sIL-6R, IL-10, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta2, interferon (IFN)-gamma, and neopterin plasma levels in patients with ATN (n=26). Matched patients with acute rejection (AR) (n=26) or normal posttransplant biopsy (n=26) served as controls.

RESULTS

Pretransplant sIL-6R was higher (P=0.0004) and pretransplant TGF-beta2 lower (P=0.002) in patients with ATN than in patients with normal biopsy. ROC curves showed that high pretransplant sIL-6R has a high sensitivity (77%) and high specificity (64%) for ATN (P=0.002). Posttransplant plasma sIL-6R continued to be higher in ATN patients than in patients with normal biopsy (P=0.001). Patients with acute rejection showed pre- and posttransplant sIL-6R and TGF-beta2 plasma levels similar to those of patients with normal biopsy (P=NS).

CONCLUSION

High pretransplant sIL-6R plasma levels are associated with an increased risk of ATN and might contribute to the development of ATN early posttransplant. Our data suggest that preactivation of the recipient's immune system increases the risk of ATN.

Perforin, Granzyme B, and fas ligand for molecular diagnosis of acute renal-allograft rejection: analyses on serial biopsies suggest methodological issues

BACKGROUND

The Perforin-Granzyme B and Fas/Fas Ligand apoptotic mechanisms are involved in the development of acute renal rejection (AR). We describe our experience of analyzing the expression of cytotoxic T-lymphotoxins (CTL) in biopsies and peripheral blood leukocytes (PBL) for the diagnosis of AR.

METHODS

We analyzed Perforin (P), Granzyme B (GB) and Fas Ligand (FL) expression in 68 renal biopsies and 64 PBL using comparative kinetic RT-PCR and, for GAPDH and FL, we also replicated with real-time RT-PCR. The levels of expression were measured in different groups, such as T0 (biopsies before reperfusion and PBL in recipient before the transplant [Tx]), Td (biopsies and PBL collected for clinical purposes) and Tp (biopsies and PBL two months after Tx).

RESULTS

A higher CTL expression was seen in non-rejecting (NR) biopsies in the first 2 months after Tx. P and FL were significantly more expressed during AR in all biopsies and in Td, while P remained upregulated in Tp. In PBL, there was no significant increase in CTL transcription during AR. A variable expression of CTL emerged in all T0 biopsies.

CONCLUSIONS

Two lytic pathways are activated in biopsies when AR occurs shortly after Tx, whereas the P/GB mechanism prevails if it occurs later on. Only P and FL in biopsies might be able to predict AR diagnosis, but with a considerable variability in each sample, possibly due to the small portion of tissue core, which may be inadequate for molecular diagnosis. CTL expression in PBL does not correlate with histological AR.

Beyond histology: novel tools to diagnose allograft dysfunction

Kidney biopsy is the gold standard procedure for the assessment of allograft dysfunction. The differential diagnosis for both acute and chronic dysfunction can encompass a number of different causes, and a biopsy frequently can suggest a specific cause. However, many of these causes are difficult to distinguish on morphologic basis alone, and the information that is obtained from a biopsy is limited with regard to functional and prognostic importance. Additional methods therefore are needed to guide the diagnosis and the treatment of allograft dysfunction, and numerous methods have been studied. Potential markers include protein and gene expression profiles in the peripheral blood, the urine, and the graft itself, all compartments that are relevant to the alloimmune response. Recent comprehensive sequencing of the human genome has led to an unprecedented opportunity to develop these genetic and proteomic techniques, and ongoing evaluations of potential tests have led to an improved understanding of the complexity of immune responses. The future challenge for promising tests is validation in larger patient populations to facilitate their addition to the diagnostic armamentarium.

Protocol Transplant Biopsies: Are They Really Needed?

Studies suggest that surveillance or protocol biopsies that are performed during the first year after kidney transplantation may be clinically useful in identifying early acute rejection or chronic allograft nephropathy at a point when they may be amenable to treatment. Although the benefit of this approach has yet to be evaluated in large, multicenter, prospective trials, numerous studies suggest that implementation of protocol biopsies may improve long-term graft function. In particular, a number of reports suggest that detection of chronic allograft nephropathy in early protocol biopsies is predictive of subsequent graft function and loss and that early treatment may have a dramatic effect on the outcome of the graft. Protocol biopsies also have the potential to be of great value in high-risk patients, such as those with delayed graft function, by allowing for early intervention for acute rejection. Furthermore, the procedure seems to be relatively straightforward and safe. Nevertheless, paucity of data has meant that clear proof of a benefit of early treatment of subclinical rejection and chronic allograft nephropathy detected by protocol biopsy is lacking. Moreover, the optimal timing of protocol biopsies and reliable methods to quantify the histologic changes observed in biopsy specimens have yet to be determined. This review discusses the pros and cons of protocol biopsies and considers the place of this procedure in the routine treatment of kidney transplant patients.

Evaluation of Biomarker Discovery Approaches to Detect Protein Biomarkers of Acute Renal Allograft Rejection†

Management of host responses to allografts by immunosuppressive therapy is the cornerstone of transplantation medicine, but it is still deficient in one important element: biomarkers that are readily accessible and predict the fate of the transplant early, specifically, and reliably. Using a Brown Norway (BN)-to-Lewis rat renal allograft model of kidney transplantation, this study aims at evaluating two proteomic approaches to discover biomarkers for acute rejection: SELDI-MS technology and 2D gel electrophoresis combined with mass spectrometry. Several novel potential serum biomarkers have been identified for follow up. Overall, the conclusion is that apparently at the serum protein level, dramatic changes only occur at a stage where kidney function is already severely affected. Multivariate analysis of serum profiles suggests that there is an ensemble of subtle changes, comprising a proteomic signature of acute rejection at an early stage, a more detailed evaluation of which might provide novel opportunities for the diagnosis of acute rejection. Profiling of the excreted proteins indicates that urine might even present the earliest signs of the rejection process.