Diagnosis Of Acute Allograft Rejection Research Articles

2706. Effectiveness and Safety of Shingrix Vaccination in Solid Organ Transplant Recipients at a Large Urban Transplant Center

Abstract Background The varicella zoster virus (VZV) recombinant subunit vaccine, Shingrix, was found to be safe in solid organ transplant recipients (SOTR) and is now approved and recommended for all immunocompromised patients. Given limited efficacy data, we preferred a single center retrospective study to demonstrate safety and effectiveness of the Shingrix vaccine in solid organ transplant recipients. Methods After IRB approval, clinical data from all SOTR at Northwestern Memorial Hospital (NMH) who received the Shingrix vaccine after their transplant, between January 1, 2017 and March 1, 2022 was collected from our Enterprise Data Warehouse (EDW). Extracted data includes age, race, ethnicity, date of transplant, organ transplanted, and date(s) of vaccine administration(s). Clinical outcomes were assessed by diagnosis of acute allograft rejection and/or HZ made post-vaccine administration. Descriptive statistics were utilized. This project is supported by the IDSA G.E.R.M. program. Results 309 of 338 eligible SOTR were included in the analysis of this study (characteristics and reasons for exclusion in Table 1). Only 1 (0.32%) patient experienced a new episode of acute allograft rejection within 3 months of Shingrix administration. 18/309 (5.8%) were diagnosed with HZ after vaccination with Shingrix. This represents a reduction in VZV reactivation events compared to the 9.1% incidence found in the 2021 meta-analysis of HZ in the general solid organ transplant population [Kwon, Transpl Infect Dis., 2021].Table 1.Characteristics of 338 solid organ transplant patients who received Shingrix vaccine. Conclusion The Shingrix vaccine, when administered to SOTR post-transplant, is safe and likely effective in reducing the rate of herpes zoster. This data supports the current recommendation to vaccinate all SOTR with Shingrix. Larger, multi-center data are needed to inform the true efficacy of the vaccine in SOTRs. Disclosures All Authors: No reported disclosures

Preliminary Investigation of the Biomarkers of Acute Renal Transplant Rejection Using Integrated Proteomics Studies, Gene Expression Omnibus Datasets, and RNA Sequencing.

A kidney transplant is often the best treatment for end-stage renal disease. Although immunosuppressive therapy sharply reduces the occurrence of acute allograft rejection (AR), it remains the main cause of allograft dysfunction. We aimed to identify effective biomarkers for AR instead of invasive kidney transplant biopsy. We integrated the results of several proteomics studies related to AR and utilized public data sources. Gene ontology (GO) and pathway analyses were used to identify important biological processes and pathways. The performance of the identified proteins was validated using several public gene expression omnibus (GEO) datasets. Samples that performed well were selected for further validation through RNA sequencing of peripheral blood mononuclear cells of patients with AR (n = 16) and non-rejection (n = 19) from our medical center. A total of 25 differentially expressed proteins (DEPs) overlapped in proteomic studies of urine and blood samples. GO analysis showed that the DEPs were mainly involved in the immune system and blood coagulation. Pathway analysis showed that the complement and coagulation cascade pathways were well enriched. We found that immunoglobulin heavy constant alpha 1 (IGHA1) and immunoglobulin κ constant (IGKC) showed good performance in distinguishing AR from non-rejection groups validated with several GEO datasets. Through RNA sequencing, the combination of IGHA1, IGKC, glomerular filtration rate, and donor age showed good performance in the diagnosis of AR with ROC AUC 91.4% (95% CI: 82–100%). Our findings may contribute to the discovery of potential biomarkers for AR monitoring.

Th17/Treg cell balance in stable liver transplant recipients

BackgroundImmune monitoring of transplanted patients may provide a reliable basis for the individualization of immunosuppressive therapy. In addition, it might be applied for realizing the early and non-invasive diagnosis of acute allograft rejection. MethodsPercentages of TCD4 + IL-17+ (Th17) and TCD4 + CD25 + CD127dim/− (Treg) cells, as well as serum levels of interleukin (IL)-17 and transforming growth factor (TGF)-β1, were evaluated in 30 stable patients using flow cytometry and ELISA techniques before and six months after liver transplantation. Besides, the same cells and cytokines were quantified in 10 recipients with acute allograft rejection. ResultsSix months post-transplant, the percentage of Th17 and Treg cells in the peripheral blood of stable liver transplant recipients reduced significantly, but the Th17/Treg ratios were comparable to the pre-transplant period (1.24 vs. 1.56); however, Th17/Treg ratios in the rejection group was significantly higher than in the stable recipients (4.06 vs. 1.56, P-value = 0.001). Stable patients showed decreased amounts of serum IL-17 which was remarkably lower than in the rejection group (P-value = 0.01). Moreover, there was a significant correlation between the serum level of IL-17 and the percentage of Th17 cells (P-value <0.001). Th17 frequency was negatively associated with the liver allograft function. Notably, TGF-β1 levels differed neither between pre-and post-transplant samplings nor between stable and rejection groups. ConclusionSix months after liver transplantation, the mean Th17/Treg ratio in stable recipients remained comparable to the pre-transplant values; however, it was significantly elevated in patients with acute allograft rejection, suggesting the Th17/Treg ratio as a probable predictor of acute rejection.

Development and validation of an optimized integrative model using urinary chemokines for noninvasive diagnosis of acute allograft rejection.

The urinary chemokines CXCL9 and CXCL10 are promising noninvasive diagnostic markers of acute rejection (AR) in kidney recipients, but their levels might be confounded by urinary tract infection (UTI) and BK virus (BKV) reactivation. Multiparametric model development and validation addressed these confounding factors in a training set of 391 samples, optimizing the diagnostic performance of urinary chemokines. CXCL9/creatinine increased in UTI and BKV viremia with or without nephropathy (BKVN) (no UTI/leukocyturia/UTI: -0.10/1.61/2.09, P=.0001 and no BKV/viremia/BKVN: -0.10/1.90/2.29, P<.001) as well as CXCL10/creatinine (1.17/2.09/1.98, P<.0001 and 1.13/2.21/2.51, P<.001, respectively). An optimized 8-parameter model (recipient age, sex, estimated glomerular filtration rate, donor specific antibodies, UTI, BKV blood viral load, CXCL9, and CXCL10) diagnosed AR with high accuracy (area under the curve [AUC]: 0.85, 95% confidence interval [CI]: 0.80-0.89) and remained highly accurate at the time of screening (AUC: 0.81, 95% CI: 0.48-1) or indication biopsies (AUC: 0.85, 95% CI: 0.81-0.90) and within the first year (AUC: 0.86, 95% CI: 0.80-0.91) or later (AUC: 0.90, 95% CI: 0.84-0.96), achieving AR diagnosis with an AUC of 0.85 and 0.92 (P<.0001) in 2 external validation cohorts. Decision curve analyses demonstrated the clinical utility of the model. Considering confounding factors rather than excluding them, we optimized a noninvasive multiparametric diagnostic model for AR of kidney allografts with unprecedented accuracy.

Diagnostic Biomarkers to Diagnose Acute Allograft Rejection After Liver Transplantation: Systematic Review and Meta-Analysis of Diagnostic Accuracy Studies.

Objective: A systematic review and meta-analysis of diagnostic biomarkers for noninvasive diagnosis of acute allograft rejection following liver transplantation.Background: Noninvasive blood and urine markers have been widely explored in recent decades for diagnosing acute rejection after liver transplantation. However, none have been translated into routine clinical use so far due to uncertain diagnostic accuracy, and liver biopsy remains the gold standard.Methods: Systematic literature searches of Medline, Cochrane and Embase were conducted up to February 2019 to identify studies evaluating the use of noninvasive markers in diagnosing allograft rejection following liver transplantation. Meta-analysis was performed using a random effects model with DerSimonian–Laird weighting and the hierarchical summary receiver operating curve.Results: Of 560 identified studies, 15 studies (1,445 patients) met the inclusion criteria. The following markers were tested: acid labile nitroso-compounds (NOx), serum amyloid A protein, procalcitonin, peripheral blood eosinophil count, peripheral blood T-cell activation and interleukin 2 (IL-2) receptor, guanylate-binding protein-2 mRNA, graft-derived cell-free DNA, pi-glutathione S-transferase, alpha-glutathione S-transferase and serum HLA class I soluble antigens. Only eosinophil count was tested in multiple studies, and they demonstrated high heterogeneity (I2 = 72% [95% CI: 0.5–0.99]). IL-2 receptor demonstrated the highest sensitivity (89% [95% CI: 0.78–0.96]) and specificity (81% [95% CI: 0.69–0.89]).Conclusion: IL-2 receptor expression demonstrated the highest diagnostic accuracy, while the peripheral eosinophil count was the only marker tested in more than one study. Presently, liver biopsy remains superior to noninvasive diagnostic biomarkers as most studies exhibited inferior designs, hindering possible translation into clinical application.

(121) - Cost-Effectiveness of a Blood-Based Biomarker Compared to Endomyocardial Biopsy for the Diagnosis of Acute Allograft Rejection

(121) - Cost-Effectiveness of a Blood-Based Biomarker Compared to Endomyocardial Biopsy for the Diagnosis of Acute Allograft Rejection

Evaluation of the Role of Conventional and Tissue Doppler Imaging Echocardiography in Detection of Acute Cardiac Allograft Rejection in Heart Transplant Recipients

Background: Endomyocardial Biopsy (EMB) is the gold standard test for diagnosis of acute allograft cardiac rejection. Objectives: The present study aimed to assess the role of echocardiographic parameters in discriminating patients with and without evidence of acute cardiac allograft rejection. Materials and Methods: In the present cross-sectional study, using convenience sampling, 63 EMB specimens were collected from the patients who had undergone biatrial orthotropic cardiac transplantation. The mean age of the recipients and donors was 30.46 ± 9.49 and 24.55 ± 7.64 years, respectively. There were 51(81%) male recipients and 39(62%) male donors. Echocardiographic examination was performed within the 24 hours of EMB. The data were entered into the SPSS statistical software, version 19 and were analyzed by chi-square test, student’s t-test, and one-way ANOVA as appropriated. All the data were two-tailed and P < 0.05 was considered to be statistically significant. Results: Among the 63 EMB specimens evaluated in the present study, mild and moderate acute rejections were seen in 19(30%) and 5(8%) cases, respectively. On Doppler examination, the three groups (without rejection, with mild rejection, and with moderate acute rejection) were significantly different only regarding trans-tricuspid E wave (P = 0.040). Pulsed-wave Tissue Doppler Imaging (TDI) also revealed a significant difference between the patients with and without allograft rejection regarding early diastolic tricuspid and mitral annular motion velocities (P = 0.005 and P = 0.02, respectively). Conclusions: It seems that echocardiographic parameters, including TDI, might be adjunct to, rather than substitution for, EMB findings for early diagnosis of acute allograft rejection.

Monitoring pharmacologically induced immunosuppression by immune repertoire sequencing to detect acute allograft rejection in heart transplant patients: a proof-of-concept diagnostic accuracy study.

BackgroundIt remains difficult to predict and to measure the efficacy of pharmacological immunosuppression. We hypothesized that measuring the B-cell repertoire would enable assessment of the overall level of immunosuppression after heart transplantation.Methods and FindingsIn this proof-of-concept study, we implemented a molecular-barcode-based immune repertoire sequencing assay that sensitively and accurately measures the isotype and clonal composition of the circulating B cell repertoire. We used this assay to measure the temporal response of the B cell repertoire to immunosuppression after heart transplantation. We selected a subset of 12 participants from a larger prospective cohort study (ClinicalTrials.gov NCT01985412) that is ongoing at Stanford Medical Center and for which enrollment started in March 2010. This subset of 12 participants was selected to represent post-heart-transplant events, with and without acute rejection (six participants with moderate-to-severe rejection and six without). We analyzed 130 samples from these patients, with an average follow-up period of 15 mo. Immune repertoire sequencing enables the measurement of a patient’s net state of immunosuppression (correlation with tacrolimus level, r = −0.867, 95% CI −0.968 to −0.523, p = 0.0014), as well as the diagnosis of acute allograft rejection, which is preceded by increased immune activity with a sensitivity of 71.4% (95% CI 30.3% to 94.9%) and a specificity of 82.0% (95% CI 72.1% to 89.1%) (cell-free donor-derived DNA as noninvasive gold standard). To illustrate the potential of immune repertoire sequencing to monitor atypical post-transplant trajectories, we analyzed two more patients, one with chronic infections and one with amyloidosis. A larger, prospective study will be needed to validate the power of immune repertoire sequencing to predict rejection events, as this proof-of-concept study is limited to a small number of patients who were selected based on several criteria including the availability of a large number of samples and the absence or presence of rejection events.ConclusionsIf confirmed in larger, prospective studies, the method described here has potential applications in the tailored management of post-transplant immunosuppression and, more broadly, as a method for assessing the overall activity of the immune system.

Noninvasive Imaging of Acute Renal Allograft Rejection by Ultrasound Detection of Microbubbles Targeted to T-lymphocytes in Rats.

We propose CD3-antibody-mediated contrast-enhanced ultrasonography using human T-lymphocytes for image-based diagnosis of acute allograft rejection (AR) established in a rat renal transplantation model. 15 minutes after tail vein injection of 30 × 10(6) human T-lymphocytes, contrast media/microbubbles conjugated with an anti-human CD3 antibody was applied to uni-nephrectomized 10-week-old allogeneically transplanted male rats (Lewis-Brown Norway (LBN) to Lewis, aTX) and ultrasound was performed to investigate the transplanted kidney as well as the native kidney. In vivo results were confirmed via immunohistochemical stainings of CD3 after post mortem dissection. Syngeneically transplanted rats (LBN to LBN, sTX), rats with ischemia/reperfusion injury (IRI, 45 min. warm ischemia), and rats subjected to acute cyclosporin A toxicity (CSA) (cyclosporine 50 mg/kg BW for 2 days i. p.) served as controls. Accumulation of human T-lymphocytes was clearly detected by antibody-mediated sonography und was significantly increased in allografts undergoing AR (5.41 ± 1.32 A. U.) when compared to native control kidneys (0.70 ± 0.08A. U.). CD3 signal intensity was low in native kidneys, sTX (0.99 ± 0.30 A. U.), CSA (0.10 ± 0.02 A. U.) and kidneys with IRI (0.46 ± 0.29 A. U.). Quantification of the ultrasound signal correlated significantly with the T-cell numbers obtained by immunohistochemical analysis (R2 = 0.57). Contrast-enhanced sonography using CD3-antibodies is an option for quick and highly specific assessment of AR in a rat model of renal transplantation.

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

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

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.

Reliability of intramyocardial electrogram for the noninvasive diagnosis of acute allograft rejection after heart transplantation in rats.

To examine the reliability of the QRS amplitude of the autonomous intramyocardial electrogram (IMEG) and the maximum slope of the descending T wave (Tslew) of the ventricular evoked response (VER) for surveillance of acute allograft rejection (AR) after heart transplantation in rats. Forty rats underwent heterotopic heart transplantation, including ten isograft (isograft group) and 30 allograft (allograft group) recipients. Autonomous IMEG and VER were recorded with epicardiac pacing leads. Isograft recipients were sacrificed on postoperative day 7 and allograft recipients on postoperative days 3, 5 and 7. Graft heart histopathological examinations were performed at the corresponding time points. Postoperative QRS amplitude and Tslew gradually decreased in the allograft group, but were unaltered in the isograft group. Decreases in the allograft group QRS amplitudes and Tslew values correlated with the histopathological results. At the optimal cutoff point of 90%, Tslew had 94.74% sensitivity, 81.82% specificity, 82.61% positive and 90% negative predictive values. QRS had 68.42% sensitivity, 90.91% specificity, 92.86% positive and 62.50% negative predictive values at its optimal cutoff point of 72.3%. The QRS amplitude of the autonomous IMEG and Tslew of VER are reliable markers for monitoring AR after heart transplantation in rats.

SPECT- and PET-based approaches for noninvasive diagnosis of acute renal allograft rejection.

Molecular imaging techniques such as single photon emission computed tomography (SPECT) or positron emission tomography are promising tools for noninvasive diagnosis of acute allograft rejection (AR). Given the importance of renal transplantation and the limitation of available donors, detailed analysis of factors that affect transplant survival is important. Episodes of acute allograft rejection are a negative prognostic factor for long-term graft survival. Invasive core needle biopsies are still the “goldstandard” in rejection diagnostics. Nevertheless, they are cumbersome to the patient and carry the risk of significant graft injury. Notably, they cannot be performed on patients taking anticoagulant drugs. Therefore, a noninvasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review SPECT- and PET-based approaches for noninvasive molecular imaging-based diagnostics of acute transplant rejection.

Remote noninvasive allograft rejection monitoring for heart transplant recipients: study protocol for the novel evaluation with home electrocardiogram and remote transmission (NEW HEART) study

BackgroundAcute allograft rejection is a major cause of early mortality in the first year after heart transplantation in adults. Although endomyocardial biopsy (EMB) is not a perfect "gold standard" for a correct diagnosis of acute allograft rejection, it is considered the best available test and thus, is the current standard practice. Unfortunately, EMB is an invasive and costly procedure that is not without risk. Recent evidence suggests that acute allograft rejection causes delays in ventricular repolarization and thereby increases the cellular action potential duration resulting in a longer QT interval on the electrocardiogram (ECG). No prospective study to date has investigated whether such increases in the QT interval could provide early detection of acute allograft rejection. Therefore, in the Novel Evaluation With Home Electrocardiogram And Remote Transmission (NEW HEART) study, we plan to investigate the potential benefit of daily home QT interval monitoring to predict acute allograft rejection.Methods/designThe NEW HEART study is a prospective, double-blind, multi-center descriptive research study. A sample of 325 adult heart transplant recipients will be recruited within six weeks of transplant from three sites in the United States. Subjects will receive the HeartView™ ECG recorder and its companion Internet Transmitter, which will transmit the subject's ECG to a Core Laboratory. Subjects will be instructed to record and transmit an ECG recording daily for 6 months. An increase in the QTC interval from the previous day of at least 25 ms that persists for 3 consecutive days will be considered abnormal. The number and grade of acute allograft rejection episodes, as well as all-cause mortality, will be collected for one year following transplant surgery.DiscussionThis study will provide "real world" prospective data to determine the sensitivity and specificity of QTC as an early non invasive marker of cellular rejection in transplant recipients during the first post-transplant year. A non-invasive indicator of early allograft rejection in heart transplant recipients has the potential to limit the number and severity of rejection episodes by reducing the time and cost of rejection surveillance and by shortening the time to recognition of rejection.Trial RegistrationClinicalTrials.gov: NCT01365806

Sequential Monitoring of TIM-3 Gene Expression in Peripheral Blood for Diagnostic and Prognostic Evaluation of Acute Rejection in Renal Graft Recipients

Background TIM-3 is expressed on primary T effector cells, including th1, ctl, and Th17, which play essential roles in acute allograft rejection (AR). In this study we monitored sequential changes of TIM-3 gene expression among peripheral blood leukocytes (PBL) from renal transplant recipients. Methods The study consisted of an AR group (n = 24), a no AR group (n = 20), and a stable group (n = 18). Prospective serial blood samples were collected after allotransplantation and during AR episodes. The mRNA encoding for TIM-3 was quantified using real-time reverse-transcription polymerase chain reaction (RT-PCR). Statistical analyses were performed to correlate gene transcript measurements with clinical events. Results TIM-3 mRNA in PBL showed significantly higher expression in the AR compared with the no AR and stable groups: 286.72 ± 86.28 vs 126.10 ± 28.31 vs 96.91 ± 17.88, respectively ( P = .00). The receiver operating characteristic curve showed a specificity of 100% and a sensitivity of 87.5% for the utility of TIM-3 for rejection diagnosis. Antirejection therapy decreased TIM-3 mRNA expression in all AR patients. There was a positive correlation between TIM-3 mRNA expression and serum creatinine ( r 2 = 0.716; P = .00). Conclusions TIM-3 mRNA quantification by RT-PCR in PBL may be a promising tool for a noninvasive diagnosis of AR. But the utility for predicting the prognosis of AR after antirejection treatment was limited, owing to the great variations of TIM-3 mRNA expression during AR episodes.

Endothelial Cell Activation Contributes to the Release of Procoagulant Microparticles During Acute Cardiac Allograft Rejection

Circulating procoagulant microparticles are reliable markers of vascular damage. The microparticle phenotypes provide additional information reflecting the nature of cell injury. This study assessed procoagulant microparticle levels and phenotypes in the diagnosis of acute allograft rejection after heart transplantation. Microparticles were prospectively investigated in the venous blood of 64 heart transplant patients, 23 with allograft rejection mainly of low score, and 41 without a rejection episode. Plasma concentrations of cytokines, cytoadhesins, and platelet activation markers were determined. By univariate analysis, the mean time elapsed from heart transplant, cold ischemia time, E-selectin-, Fas- and tissue factor-bearing microparticles were associated with allograft rejection. By multivariate analysis, E-selectin-microparticle levels appeared independently associated with allograft rejection, even when other significant variables were included in the model (odds ratio, 9.8; 95% confidence interval, 1.36-71.4; p = 0.023). The pattern of procoagulant microparticles released during acute allograft rejection suggests endothelial cell activation and Fas-mediated apoptosis. E-selectin-bearing microparticles appeared as an independent marker of acute allograft rejection that was still informative after adjustment for graft characteristics.

Renal transplant biopsy specimen adequacy in a paediatric population

Updated guidelines on the diagnosis of acute allograft rejection including criteria for biopsy specimen adequacy were published in 1999. We sought to determine the adequacy of specimens in paediatric transplant patients and identify factors influencing adequacy. All renal transplant biopsies performed between 1998 and 2003 were classified as adequate (n =25), minimal (n =19) or inadequate (n =27) in accordance with the Banff 97 criteria, and the histological diagnoses were documented. The effect on specimen adequacy of grade of operator, method of sedation, age of child, needle gauge, number of cores and total core length was then investigated. Overall, a minimal or adequate specimen was obtained in 62% of cases. No histological diagnosis could be made in 30% of all specimens, just over half of which were inadequate. Higher rates of rejection were found in adequate (52%) than inadequate (33%) samples. The grade of operator (p =0.498), the age of the child at the time of biopsy (p =0.815) and type of sedation (p =0.188) did not affect adequacy. More than one core was obtained in 38 (54%) cases, and this was significantly associated with specimen adequacy (p <0.0005) as was longer total core length (p =0.002). Clinical features in isolation are not sufficient for the diagnosis of acute allograft rejection. Renal biopsy remains the gold standard and relies on adequate specimen collection. Our data shows that specimen adequacy according to the Banff 97 guidelines is achievable in children and that more than one core at the time of sampling significantly improves this achievement. Adequate sampling reduces the risk of an inconclusive histological diagnosis.

Prediction of Acute Renal Allograft Rejection by Urinary Monokine Induced by IFN-γ (MIG)

Early diagnosis of acute allograft rejection (AR) is still decisive for long-term renal allograft survival. The aim of this study was to define the role of the chemokine monokine induced by IFN-gamma (MIG) (CXCL9) and IFN-gamma-inducible protein 10 (IP-10) (CXCL10) as early markers of AR in renal transplantation (NTX). In a prospective study, 69 de novo renal transplant recipients were monitored and urine samples were collected after NTX for a median of 29 d. In pH-adjusted urine, MIG and IP-10 were determined by modified ELISA. AR was clinically diagnosed in 15 of 69 recipients and confirmed by biopsy in 14 of 15 AR patients (Banff classification). Corresponding to CXCR3-positive infiltrates in renal tissue, urinary MIG was elevated in 14 of 15 AR patients with a median of 2809 pg/ml (quartile 25% and 75% = 870 and 13,000; n = 15), being significantly (P < 0.0001) different from both nonrejecting allograft patients (NO-AR) (median, 25%, and 75%: 96, 1.0, and 161, n = 54) and healthy controls (median, 25%, and 75%: 144, 19, and 208, n = 13). Urinary MIG predicted AR with a sensitivity of 93% and a specificity of 89%. In AR and NO-AR groups, MIG values correlated well with IP-10 (P < 0.001). MIG values indicated both imminent rejection and response to successful antirejection therapy. MIG was not related to intercurrent infections or other causes for impairment of renal function. In a multivariate analysis, MIG correlated best (P < 0.001) with AR from all AR-associated parameters. In conclusion, urinary MIG serves as a very sensitive and specific predictor for AR, mirrors response to antirejection therapy, and thus may contribute to improved long-term renal allograft survival.

Immunocytological determination of lymphocytes and monocytes/macrophages in urinary sediments of renal allograft recipients.

Urinary studies using Papanicolaou staining following kidney transplantation led to the conjecture that acute allograft rejection might be accompanied by an increased lymphocyturia. However, it is difficult to distinguish lymphoid cells from other urinary cells using conventional stains. Staining of urinary lymphocytes using FITC-labelled antibodies is complicated by a high unspecific fluorescence that limits the evaluation. Therefore, we developed a method to stain urinary lymphocytes using enzyme-linked antibodies. The cells were cytocentrifuged onto microscope slides and were fixed. By means of a combined evaluation of Papanicolaou and immunocytochemical staining, CD3-positive pan T cells, CD4-positive T-helper cells, CD8-positive cytotoxic/suppressor cells, and CD14-positive monocytes/macrophages of urinary sediments were determined in 41 kidney graft recipients following renal transplantation. During periods of normal graft function, neither positive lymphocytes nor positive monocytes/macrophages were found in the urinary sediments. However, in the course of acute allograft rejection a significant increase in positive lymphocytes and positive monocytes/macrophages could be observed. Interestingly, in cases of acute allograft rejection the distribution of urinary lymphocytes and monocytes was comparable to the distribution of infiltrating immunocompetent cells in renal allograft biopsies. The present study demonstrates that immunocytochemical staining via enzyme-conjugated antibodies is a reliable method to visualize T lymphocytes and monocytes/macrophages in the urinary sediment, and that this technique may be of special diagnostic value in the diagnosis of acute allograft rejection.

Diagnosis of heart graft rejection

Despite refinements in immunosuppressive therapy, acute allograft rejection remains a major cause of mortality in heart transplant recipients. The high reliability, noninvasiveness, possibility of day-to-day monitoring, absence of interobserver variability, and cost effectiveness are essential components of the ideal diagnostic method for the detection of allograft rejection. This paper reviews the experimental and clinically established methods for the diagnosis of acute allograft rejection. The most promising tools seem to be electrophysiologic, because these tools provide the potential for continuous noninvasive distant rejection monitoring, and echocardiographic techniques that enable the safe assessment of changes in cardiac structure and function and further reduce the need for endomyocardial biopsy and, more importantly, provide a better definition of the threshold for antirejection treatment. Additional research and refinements of techniques and evaluation in prospective randomized multicenter studies are needed to further advance the use of noninvasive methods for diagnosis of heart graft rejection.