Early Diagnosis Of Acute Rejection Research Articles

ESTABLISHMENT OF EARLY WARNING MODEL OF ACUTE REJECTION IN COMBINATION WITH HLA-G 14-BP GENE POLYMORPHISM, SERUM KIM-1AND OPN

Introduction: Acute rejection is an important cause of renal allograft loss. There is an urgent need to find an atraumatic marker that can be used alone or in combination with other indicators to make an early diagnosis of acute rejection, so that anti-rejection treatment can be performed in time before renal tissue damage occurs, which protects the function of the graft and enables the graft to survive for a long time. In the present study, we tried to further establish an early warning model of acute rejection by combining the three indicators of HLA-G 14-bp genotyping test, serum KIM-1 on the first postoperative day and serum OPN on the seventh postoperative day. Methods: We conducted a single-center study of 77 subjects, who were classified into acute rejection group (AR, n=32) and stable allograft function group (STA, n=45).All kidney transplant recipients received 2 ml of EDTA anticoagulated peripheral venous blood before kidney transplantation, and performed HLA-G 14-bp gene polymorphism typing. Serum KIM-1 level on the first postoperative day and OPN level on the 7th postoperative day were measured by Luminex. The study was approved by the local ethical committee. All patients with end-stage renal disease underwent kidney transplantation with living-related donor. The HLA-G+14/+14-bp genotype was significantly associated with acute rejection after transplantation. Therefore, we define recipients of the HLA-G+14/+14-bp genotype as positive, while HLA-G+14/−14-bp genotype and HLA-G−14/−14-bp genotype recipients are defined as negative. Serum KIM-1 on the first postoperative day was defined as positive if greater than 153 pg/ml and negative as less than 153 pg/ml; Serum OPN on the seventh postoperative day was defined as positive and less than 21921 pg/ml Defined as negative. Results: We have established three early warning models for acute rejection (Table 1)and found that Model 2 is the model with two or more positive diagnostic indicators. The ability to early alert acute rejection is the strongest, and the Youden index is the largest (0.75). The specificity was 84.38% and 91.11%, the positive predictive value and negative predictive value were 87.10% and 89.13%, respectively, and the average occurrence of acute rejection could be warned 6.44±6.12 days in advance (Table 2).The ability of Model 2 to early alert acute rejection is stronger than the other two models, becoming the best model for early warning of acute rejection in this study. Conclusions: We combined the HLA-G 14-bp genotyping test, serum KIM-1 on the first postoperative day, and OPN on the seventh postoperative day to establish three early warning models for acute rejection. Among the three models, the sensitivity and specificity of two or more positive indicators for early warning of acute rejection were 84.38% and 91.11%, which could predict the occurrence of acute rejection in advance.

Donor tissue-specific exosome profiling enables noninvasive monitoring of acute rejection in mouse allogeneic heart transplantation

ObjectiveIn heart transplantation, there is a critical need for development of biomarkers to noninvasively monitor cardiac allografts for immunologic rejection or injury. Exosomes are tissue-specific nanovesicles released into circulation by many cell types. Their profiles are dynamic, reflecting conditional changes imposed on their tissue counterparts. We proposed that a transplanted heart releases donor-specific exosomes into the recipient's circulation that are conditionally altered during immunologic rejection. We investigated this novel concept in a rodent heterotopic heart transplantation model. Materials and MethodsFull major histocompatibility mismatch (BALB/c [H2-Kd] into C57BL/6 [H2-Kb]) heterotopic heart transplantation was performed in 2 study arms: Rejection (n = 64) and Maintenance (n = 28). In the Rejection arm, immunocompetent recipients fully rejected the donor heart, whereas in the Maintenance arm, immunodeficient recipients (C57BL/6 PrkdcSCID) accepted the allograft. Recipient plasma exosomes were isolated and a donor heart-specific exosome signal was characterized on the nanoparticle detector for time-specific profile changes using anti-H2-Kd antibody quantum dot. ResultsIn the Maintenance arm, allografts were viable throughout follow-up of 30 days, with histology confirming absence of rejection or injury. Time course analysis (days 1, 2, 3, 4, 5, 7, 9, 11, 15, and 30) showed that total plasma exosome concentration (P = .157) and donor heart exosome signal (P = .538) was similar between time points. In the Rejection arm, allografts were universally rejected (median, day 11). Total plasma exosome quantity and size distribution were similar between follow-up time points (P = .278). Donor heart exosome signals peaked on day 1, but significantly decreased by day 2 (P = 2 × 10−4) and day 3 (P = 3.3 × 10−6), when histology showed grade 0R rejection. The receiver operating characteristic curve for a binary separation of the 2 study arms (Maintenance vs Rejection) demonstrated that a donor heart exosome signal threshold < 0.3146 was 91.4% sensitive and 95.8% specific for diagnosis of early acute rejection. ConclusionsTransplant heart exosome profiling enables noninvasive monitoring of early acute rejection with high accuracy. Translation of this concept to clinical settings might enable development of a novel biomarker platform for allograft monitoring in transplantation diagnostics.

Metabolomics identifies metabolite biomarkers associated with acute rejection after heart transplantation in rats

The aim of this study was to identify metabolite biomarkers associated with acute rejection after heart transplantation in rats using a LC-MS-based metabolomics approach. A model of heterotopic cardiac xenotransplantation was established in rats, with Wistar rats as donors and SD rats as recipients. Blood and cardiac samples were collected from blank control rats (Group A), rats 5 (Group B) and 7 days (Group C) after heart transplantation, and pretreated rats 5 (Group D) and 7 days (Group E) post-transplantation for pathological and metabolomics analyses. We assessed International Society for Heart and Lung Transplantation (ISHLT) grades 0, 3B, 4, 1 and 1 rejection in groups A to E. There were 15 differential metabolites between groups A and B, 14 differential metabolites between groups A and C, and 10 differential metabolites between groups B and C. In addition, four common differential metabolites, including D-tagatose, choline, C16 sphinganine and D-glutamine, were identified between on days 5 and 7 post-transplantation. Our findings demonstrate that the panel of D-tagatose, choline, C16 sphinganine and D-glutamine exhibits a high sensitivity and specificity for the early diagnosis of acute rejection after heart transplantation, and LC-MS-based metabolomics approach has a potential value for screening post-transplantation biomarkers.

Clinical and pathological analysis of acute rejection following orthotopic liver transplantation.

Acute rejection is one of the most important factors for prognosis following liver transplantation. With the use of potent immunosuppressants, acute rejection does not always present typical manifestations. Moreover, other complications often occur concomitantly after liver transplantation, which makes early diagnosis of acute rejection more difficult. Acute rejection is best diagnosed by liver biopsy. Differentiation of clinical manifestations and pathological features plays an important role in achieving individualized immunosuppressive treatment and prolonging long term survival of patients given orthotopic liver transplants. From January 2004 to December 2006, 516 orthotopic liver transplantations were performed at the First Affiliated Hospital, Sun Yat-sen University. For patients who suffered acute rejection, clinical manifestations, histopathological features, diagnosis and anti-rejection treatment were summarized and analyzed. In 86 cases (16.7%), of the 516 recipients, 106 episodes of acute rejection occurred, which included 9 with histopathological borderline changes, 36 Banff I rejections, 48 Banff II and 13 Banff III. Among these, 36 were cured by adjusting the dose of immunosuppressant and 65 were reversed by methylprednisolone pulse treatment. Five were methylprednisolone resistant, 3 of whom were given OKT3 treatment and 2 underwent liver retransplantation. Due to potent immunosuppressive agents, acute rejection following an orthotopic liver transplantation lacks typical clinical manifestations and pathological features. Acute rejection is best diagnosed by liver biopsy. Designing rational individualized immunosuppressive regimen based on clinical and pathological features of acute rejection plays an important role in prolonging long term survival of patients.

Urine protein profiling identified alpha-1-microglobulin and haptoglobin as biomarkers for early diagnosis of acute allograft rejection following kidney transplantation

Early diagnosis of acute rejection and effective immunosuppressive therapy lead to improvement in graft survival following kidney transplantation. In this study, we aimed to establish a urinary protein profile suitable to distinguish between patients with rejection and stable graft function and to predict acute rejection based on postoperatively collected urine samples. A further objective was to identify candidate proteins for the use as biomarkers in clinical practice. Urine samples of 116 kidney recipients were included. Rejection was proven by biopsy (n = 58), and stable transplant function was monitored for at least 2 years (n = 58). Postoperative urine samples were collected between 3rd and 10th day following transplantation. Urinary protein profiles were obtained by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Protein identification and validation were performed using multiplex fluorescence 2DE, peptide mass fingerprinting and enzyme-linked immunosorbent assay. A protein profile including four mass peaks differentiated acute rejection from stable transplants at the time point of rejection and at the postoperative state with 73 % sensitivity and 88 % specificity. Alpha-1-microglobulin (A1MG) and Haptoglobin (Hp) were identified as putative rejection biomarkers. Protein levels were significantly higher in postoperative urine from patients with rejection (A1MG 29.13 vs. 22.06 μg/ml, p = 0.001; Hp 628.34 vs. 248.57 ng/ml, p = 0.003). The combination of both proteins enabled the diagnosis of early rejection with 85 % sensitivity and 80 % specificity. Protein profiling using mass spectrometry is suitable for noninvasive detection of rejection-specific changes following kidney transplantation. A specific protein profile enables the prediction of early acute allograft rejection in the immediate postoperative period. A1MG and Hp appear to be reliable rejection biomarkers.

Serum levels of CXCR3 ligands predict T cell-mediated acute rejection after kidney transplantation

The early diagnosis of acute rejection is crucial for graft survival after kidney transplantation. The interferon-γ (IFNγ)-CXCR3-chemokine-dependent inflammatory loop plays a pivotal role in the recruitment of Tlymphocytes during acute rejection. Previously published studies have typically focused on the CXCR3 receptor rather than on its ligands. In the present study, we used Luminex assays to detect the levels of CXCR3 ligands, monokine induced by IFNγ (MIG), IFN-induced protein10 (IP-10) and IFN-induced T‑cell chemoattractant (I-TAC), in the serum of renal allograft recipients. According to a renal biopsy performed one month after kidney transplantation, 32recipients were diagnosed with Tcell-mediated acute rejection and 38patients were evaluated as stable. Serum was collected after the diagnosis of acute rejection or one month after transplantation. The concentrations of MIG (median, 4,271pg/ml), IP-10 (median,686.7pg/ml) and I-TAC (median,44.32pg/ml) in the serum during an acute rejection episode were significantly higher compared with those of the stable patients (MIG, P=0.0002; IP-10, P=0.0001; I-TAC, P=0.0103; vs. the stable function group, P<0.05). Based on the receiver-operating characteristic (ROC) curve, the joint detection of MIG, IP-10 and I-TAC in the serum using Luminex analysis may constitute a non-invasive and efficient method for the early prediction of Tcell-mediated acute rejection following kidney transplantation.

Erratum to: Neutrophil gelatinase-associated lipocalin is a sensitive biomarker for the early diagnosis of acute rejection after living-donor kidney transplantation

Erratum to: Neutrophil gelatinase-associated lipocalin is a sensitive biomarker for the early diagnosis of acute rejection after living-donor kidney transplantation

Neutrophil gelatinase-associated lipocalin is a sensitive biomarker for the early diagnosis of acute rejection after living-donor kidney transplantation

Early diagnosis of kidney allograft dysfunction is crucial for the management and long-term survival of transplanted kidneys. We investigated whether neutrophil gelatinase-associated lipocalin (NGAL), interleukin 18 (IL-18), and liver-type fatty acid-binding protein (L-FABP) are capable of being used as novel biomarkers of acute kidney allograft dysfunction. We measured serum and urine NGAL, urine IL-18, and urine L-FABP levels on the first 3 days after transplantation. To assess the diagnostic sensitivity of these biomarkers, a receiver-operating characteristic curve (ROC) was plotted, and the area under the curve (AUC) was calculated to quantify the accuracy of the parameter. Sections from paraffin-embedded biopsy specimens were examined by immunohistochemistry for NGAL expression. Twelve cases were clinically diagnosed as acute rejection (AR) by renal biopsy. Urine NGAL was the most sensitive of these markers for detection of acute kidney allograft dysfunction. The cutoff value of urine NGAL was 66.0 ng/ml, with an AUC of 0.79 (95 % CI 0.68-0.88). Sensitivity of serum NGAL was about the same as urine NGAL with an AUC of 0.75 (0.64-0.85). IL-18 and L-FABP were 0.584 (95 % CI 0.433-0.725) and 0.612 (95 % CI 0.460-0.749), respectively. NGAL was more useful than other biomarkers to detect AR of kidney allograft dysfunction. NGAL staining intensity was significantly increased in the proximal tubules of the transplants with AR than in transplants that were not acutely rejected. Urine NGAL level was found to be the most sensitive biomarker of acute kidney allograft dysfunction after living-donor kidney transplantation.

A Case of Acute Antibody-Mediated Rejection Developed after Pretreatment with Rituximab and Plasma Exchange in a Highly-Sensitized Recipient with a Deceased Donor Kidney

Acute antibody-mediated rejection is the major cause of graft failure in the early stage of kidney transplantation. Preoperative treatment and early diagnosis of acute rejection is very important to prevent graft loss in sensitized patients. High panel reactive antibody (PRA) means a likelihood of acute rejection, and the recipient of high PRA needs adequate pretreatment for kidney transplantation. However, there is not sufficient time and chances for desensitization in deceased kidney transplants. We report a successful renal transplant outcome in a 47-year-old-woman with high PRA levels (Class I 97.5%, Class II 36.7%). The cross match was negative on the CDC (ELISA) and flowcytometric methods. Plasma exchange was performed on the recipient before transplantation (fresh frozen plasma replacement, 1.3 plasma volume) and immediately after plasma exchange she was given 200 mg of rituximab. She received basiliximab and methyl prednisolone induction therapy and was maintained on steroids, mycophenolate mofetil, and tacrolimus. Graft function was normal immediately after transplantation, but decreased urinary output and elevated serum creatinine was noted on POD 5. On POD 6, a graft biopsy revealed acute cellular rejection (Type IIa) and antibody-mediated rejection (Type II). On 9∼13 days after transplantation, additional plasma exchange was performed every other day, and steroid pulse therapy was performed 3 times. After normalization of urinary output and serum creatinine, the patient was discharged and is being followed up on. In conclusion, immunologically careful preparation and pretransplant treatment may be needed on the negative cross match in cadaveric kidney recipients with high levels of PRA.

Detection of urinary biomarkers for early diagnosis of acute renal allograft rejection by proteomic analysis

Acute allograft rejection has been recognized as a major impediment to improved success in renal transplantation. Timely detection and control of rejection are very important for the improvement in long-term renal allograft survival. Thus, biomarkers for early diagnosis of acute rejection are required urgently to clinical medication. This study seeks to search for such biomarker candidates by comparing patients' pre-treatment urinary protein profiling with their post-treatment urinary protein profiling. A total of 15 significantly and consistently down-regulated protein candidates were identified. Among them, alpha-1-antichymotrypsin precursor (AACT), tumor rejection antigen gp96 (GP96) and Zn-Alpha-2-Glycoprotein (ZAG) were selected for further analysis. The results indicated that Western Blot assay of AACT, GP96 and ZAG had advanced the diagnosis time of acute renal rejection by 3 days, compared with current standard clinical observation and laboratory examination. Furthermore, the double-blind detection revealed that the accuracy, sensitivity and specificity of the diagnosis of acute renal rejection of AACT, GP96 and ZAG were 66.67%/100%/60%, 83.33%/100%/80% and 66.67%/100%/60%, respectively, and 100%/100%/100% in combination. In conclusion, urinary protein AACT, GP96 and ZAG could be a set of potential biomarkers for early non-invasive diagnosis of the acute rejection after renal transplantation.

Gene expression profiling on acute rejected transplant kidneys with microarray

To investigate the gene expression profiles in acute allograft rejection of renal transplantation, and identify the markers for the early diagnosis of acute rejection, heterotopic kidney transplantation was performed by using F344 or Lewis donors and Lewis recipients. No immunosuppressant was used. Renal grafts were harvested on days 3, 7, and 14. A commercial microarray was used to measure gene expression levels in day-7 grafts. The expression levels of 48 genes were up-regulated in the allograft in comparison with the isograft control, and interferon-gamma-induced GTPase gene was most significantly up-regulated in allografts. It is concluded that a variety of pathways are involved in organ transplant rejection which is dynamic and non-balanced. IFN-inducible genes, such as IGTP, may play an important role in the rejection. A lot of important factors involved in acute rejection are unnecessary but sufficient conditions for the rejection. We are led to conclude that it is virtually impossible to make an early diagnosis based on a single gene marker, but it could be achieved on the basis of a set of markers.

The role of sICAM-1 detection in the diagnosis of acute rejection following liver transplantation

In order to evaluate the applied value of soluble intracellular adhesion molecule-1 (sICAM-1) in acute rejection (AR) following liver transplantation, the expression of sICAM-1 protein was sequentially detected by using ELISA in serum and bile of 43 patients receiving liver transplantation. In AR group, the expression levels of sICAM-1 protein were increased 3 days before and immediately on the establishment of AR diagnosis, and there was significant difference in the expression of bile between AR group and control group (P<0.01). After reversion of AR with hormone intensive therapy, there was significant difference in the sICAM-1 protein expression of serum and bile between AR group and control group. It was concluded that the sequential detection of sICAM-1 protein level in serum and bile was a reliable and noninvasive method for the early diagnosis of AR after liver transplantation and was valuable to observe the curative effects of anti-AR therapy.

Quantification of donor-derived DNA in serum: A new approach of acute rejection diagnosis in a rat kidney transplantation model

Clinical and laboratory findings of acute rejection (AR) are often late and misleading. Core needle biopsy, the most reliable diagnostic method, is usually performed late in the course of AR and is associated with several complications. Therefore noninvasive approaches to monitor the immune system for detection of early AR is one of the major aims in transplant medicine. In a fully MHC-mismatched renal allograft model in the rat, we quantified donor-derived DNA (ddDNA) in the recipient serum using real-time RT-PCR as an alternative screening procedure for the early diagnosis of acute rejection. We also investigated the influence of different immunosuppressive protocols on the levels of ddDNA. Our results show that donor-derived DNA is present in the serum of kidney allograft recipients prior to acute rejection. Animals that received a syngeneic graft and animals that received a mismatched allograft but were treated with immunosuppressive drugs did not show significant elevations of ddDNA. When steroid therapy failed to avoid acute rejection, the animals showed a delayed peak of ddDNA. In summary, the detection of ddDNA in recipient serum offers a noninvasive diagnostic approach to uncover ongoing rejection processes in the graft.

Graft mucosal blood flow is reduced prior to histologic evidence of rejection in mouse small bowel transplantation: a murine model

THE SUCCESS of small bowel transplantation is hampered by vigorous and early acute rejection responses. At present, the diagnosis of acute rejection is based mainly on histology and endoscopy. The late onset of morphologic changes and the initial patchy pattern makes it hard to discover early. Therefore efforts continue to identify novel and effective means for early diagnosis of acute rejection in intestinal transplantation. It has been demonstrated that one of the first targets in acute rejection of the small bowel allograft is the vascular endothelial cells in the lamina propria. This response may result in early mucosal microcirculatory disturbances and progressive ischemia that eventual lead to morphologic changes. We assumed that this attack on the microvasculature would be reflected in mucosal blood perfusion. Mucosal perfusion was measured by means of laser Doppler flowmetry at different time intervals and compared with synchronous histologic samples.

Quantitative analysis of cardiac 3-L-nitrotyrosine during acute allograft rejection in an experimental heart transplantation.

Recent studies have shown that nitric oxide interacts with superoxide to form peroxynitrite, a potent oxidant that modifies cellular proteins producing 3-L-nitrotyrosine (N-Tyr). This study was designed to evaluate N-Tyr quantitatively with high-performance liquid chromatography (HPLC) during cardiac allograft rejection. Rat transplanted hearts (allogeneic or syngeneic grafts) were examined with HPLC analysis, immunohistochemistry for N-Tyr, and histological studies on 0, 1, 3, and 7 days after transplantation. No histological rejection was found in syngeneic grafts, or day 0 or 1 allografts. HPLC demonstrated that N-Tyr in allografts increased on day 1 and continued to increase through day 7, while N-Tyr was not detected in any syngeneic grafts. Immunostaining of the allografts did not show N-Tyr on day 1. These results demonstrate that N-Tyr shows a time-dependent accumulation in cardiac allografts during acute rejection. N-Tyr detection using HPLC may be an useful maker for early diagnosis of acute rejection before pathological rejection occurs.

Monitoring eosinophil activation and liver function after liver transplantation.

Portal tract eosinophil infiltration and an increase in the blood eosinophil count (EOS) have been shown to be specific markers of liver allograft rejection. The graft eosinophil infiltration is associated with the local release of eosinophil cationic protein. Therefore, serum eosinophil cationic protein concentration (ECP) is a potential marker for acute allograft rejection. We investigated the chronological relationship among and diagnostic value of serial changes in EOS, ECP, and liver function tests (LFTs) following liver transplantation. EOS, ECP, serum alpha-glutathione S-transferase concentration, and conventional LFTs were measured in serial samples collected over the first 3 postoperative months following 58 liver transplants. The diagnostic potential of each test, alone or in combination, was reviewed over the entire follow-up period. EOS and ECP increased at a median period of 3.5 and 4 days, respectively, before the diagnosis of acute rejection, and this increase was significantly earlier than the corresponding changes in LFTs (P<0.05). There was a significant correlation between the day of the first increase in EOS and alpha-glutathione S-transferase (rs=0.535; P=0.009) and EOS and alanine transaminase (rs=0.629; P=0.004). The optimum combination of tests for the diagnosis of acute rejection was an increase in both EOS and GST with a predictive efficiency of 84%. Increases in EOS and ECP are early indicators of acute liver allograft rejection and precede evidence of hepatocellular damage. However, an increase in ECP was also frequently associated with infection. Therefore, we recommend the regular monitoring of EOS in conjunction with routine LFTs after liver transplantation as an aid to the early diagnosis of acute rejection.

Diagnosis of early acute renal allograft rejection by evaluation of multiple histological features using a Bayesian belief network.

BACKGROUND AND AIMS: The development of the Banff classification of renal transplant pathology has allowed the standardisation of approaches to transplant biopsy histology and reduced interobserver and interdepartmental variation. The...

Sequential monitoring of urine-soluble interleukin 2 receptor and interleukin 6 predicts acute rejection of human renal allografts before clinical or laboratory signs of renal dysfunction.

The significance of noninvasive techniques to the early diagnosis of acute rejection in kidney transplants remains elusive. In this study, we examined whether an early posttransplant increase in serum- and urine-soluble interleukin (IL) 2 receptor (sIL-2R) and IL-6 levels predicted acute rejection. Sequential determinations of serum and urine sIL-2R and IL-6 were performed in the first 30 postoperative days in 40 renal transplant patients. Changes during the posttransplant period observed in 26 patients who had one or more episodes of acute rejection (group A) were compared with those recorded in 14 patients who did not experience acute rejection of their graft (group B). Serum sIL-2R was higher than normal in patients of groups A and B without statistical differences between the two groups. In the first 3 days after transplantation, urinary sIL-2R was higher than normal in group A but not in group B. Urinary sIL-2R at days 2 and 3 was significantly higher (P<0.05) in group A than in group B. In the first 5 days after transplantation, urinary IL-6 was persistently higher than normal in group A, whereas it progressively decreased to normal value on day 4 in group B. Sudden increases (doubling within 24 hr) in urine IL-6 preceded clinical diagnosis of acute rejection by a mean period of 2 days, with an 87% sensitivity and a 64% specificity, and also predicted recurrent rejection episodes. Sequential monitoring of urinary sIL-2R and IL-6 levels does allow very early diagnosis of rejection without invasive procedures. Specifically, high urinary sIL-2R in the first 5 posttransplant days identifies the subgroup of patients at risk. In the subsequent days, a sudden increase in urinary IL-6 occurs in those of the above patients who will indeed reject their graft.

Serum amyloid A protein is a clinically useful indicator of acute renal allograft rejection.

Early diagnosis of acute rejection after renal transplantation is important. There is evidence that measurement of the acute phase proteins, C-reactive protein (CRP) and serum amyloid A protein (SAA) is helpful. In 64 consecutive patients, CRP was measured in a routine clinical system (Technicon RA1000, Bayer) and SAA in a new sensitive automated immunoassay on the Abbott IMx instrument, daily or on alternate days for 30 days after renal transplantation. Patients all received triple immunosuppression with cyclosporin, azathioprine, and prednisolone and all mounted a post-surgical acute phase response of SAA, but the CRP response was reduced or absent. Serum creatinine rose significantly in 36 patients, leading to treatment for first rejection. Thirty of these episodes were confirmed rejection, three were definitely not and three were uncertain. SAA. normally < 10 mg/l, rose to more than 100 mg/l in all episodes except when rejection was definitely absent. In six cases SAA rose above 100 mg/l 1-3 days before the rise in creatinine leading to antirejection therapy, and only twice did creatinine rise 1 day before SAA. In contrast, CRP responses to rejection were modest or absent. In four patients there were SAA and CRP responses unrelated to rejection, three associated with intercurrent infection and one with administration of antilymphocyte globulin. There were also two unexplained isolated spikes of SAA. SAA is a sensitive marker of acute renal allograft rejection. It is not specific, but the differential behaviour of CRP in patients receiving cyclosporin helps to distinguish infection from rejection. Availability of rapid assays for these analytes should facilitate management of renal allograft recipients.

Diagnostic value of urinary enzyme determination in renal transplantation

Abstract The measurement of enzyme activity in urine provides a sensitive assessment for renal tubular cell damage. The present study was undertaken to evaluate the clinical value of the determination of tubular brush-border-associated enzymes, alkaline phosphatase (AP), gamma-glutamyl transferase (GGT), leucine aminopeptidase (LAP), and dipeptidyl peptidase IV (DPP), of patients with normal graft function (NOR, n= 20), with acute tubular necrosis (ATN, n= ll), with an acute rejection episode (ARE, n= 17) after transplantation, and of healthy persons (n=20). The second urine of the morning was collected daily during the patients' stay in hospital. The enzyme activities were measured at 25 °C and were expressed as U/mmol creatinine. The enzymuria in NOR is higher than in healthy controls, but is still in the normal range. By 5 days after transplantation the initial increased excretion declines as the graft function improves. Elevated enzymuria (DPP 0.69 ± 0.56, AP 3.06 ± 3.24, GGT 4.16 ± 4.13, and LAP 1.39 ± 1.27) was observed during the rejection episodes. Two days before clinical diagnosis of rejection, the release of DPP-IV and GGT increases to double, and the AP and LAP increases to 3 times the value on the fourth day before rejection. Successful treatment of rejection coincided with a quick return by the third day of the rejection period to the previous enzyme distribution. In ATN no decrease of enzymuria occurs and the excretion is much higher than in ARE. Our method with the every day monitoring of kidney graft function offers the possibility for the early diagnosis of acute rejection.