Diagnosis Of Acute Antibody-mediated Rejection Research Articles

Plasma miR-150-5p in Renal Transplant Recipients with Acute Antibody-Mediated Rejection.

Background: Rejection continues to be the main cause of renal graft loss. Currently, the gold standard for diagnosis is an allograft biopsy; however, because it is time-consuming, costly, and invasive, the pursuit of novel biomarkers has gained interest. Variation in the expressions of miRNAs is currently considered a probable biomarker for the diagnosis of acute rejection. This study aimed to determine whether miR-150-5p in serum is related to microvascular damage in patients with acute antibody-mediated rejection (ABMR). Methods: A total of 27 patients who underwent renal transplantation (RT) with and without ABMR were included in the study. We performed the quantification of hsa-miR-150-5p, hsa-miR-155, hsa-miR-21, hsa-miR-126, and hsa-miR-1 in plasma by RT-qPCR. The expressions between the groups and their correlations with the histological characteristics of the patients with ABMR were also investigated. Results: miR-150-5p significantly increased in the plasma of patients with rejection (p < 0.05), and the changes in miR-150-5p were directly correlated with microvascular inflammation in the allograft biopsies. Clinical utility was determined by ROC analysis with an area under the curve of 0.873. Conclusions: Our results show that the patients with RT with ABMR exhibited increased expression of miR-150-5p compared to patients without rejection, which could have clinical consequences, as well as probable utility in the diagnosis of ABMR, and bioinformatics may help in unraveling the molecular mechanisms underlying ABMR conditions.

The diagnosis of acute antibody-mediated rejection was delayed due to the initial suspicion of graft dysfunction caused by renal artery stenosis

The diagnosis of acute antibody-mediated rejection was delayed due to the initial suspicion of graft dysfunction caused by renal artery stenosis

Acute Antibody-mediated Rejection Coexisting With T Cell-mediated Rejection in Pediatric ABO-incompatible Transplantation.

Background.The management and outcome of ABO-incompatible (ABO-I) liver transplantation (LT) has been improving over the past few decades. Recently, the introduction of a pathological evaluation of acute antibody-mediated rejection (AMR) for liver allograft has provided a new recognition of allograft rejection in LT.Methods.One hundred and one pediatric ABO-I LTs performed in our institute were retrospectively analyzed. We assessed the clinical manifestations, diagnosis, and treatment of acute AMR, focusing on the recipient age and pathological findings.Results.Twelve cases (11.9%) of acute AMR related to ABO-I were observed. Nine cases developed mixed T cell–mediated rejection (TCMR)/AMR. These consisted of 6 patients in the younger age group for whom the preconditioning treatment was not indicated and 4 patients in the older age group to whom rituximab was administered as planned. Two patients in the older age group to whom preoperative rituximab was not administered as planned developed isolated AMR. Acute AMR in the older group required plasma exchange for treatment, regardless of the coexistence of TCMR. In contrast, those in the younger group were successfully treated by intravenous methylprednisolone pulse and intravenous immunoglobulin without plasma exchange, accounting for mild immune reaction.Conclusions.Acute ABO-I AMR can develop simultaneously with TCMR, even in young patients with a compromised humoral immune response following ABO-I LT. Establishing the accurate diagnosis of AMR with a pathological examination, including component 4d staining, is crucial for optimizing treatment.

COMPARISON OF DIFFERENT METHODS OF ANTI-HLA ANTIBODIES DETECTION IN DIAGNOSIS OF ANTIBODY-MEDIATED RENAL ALLOGRAFT REJECTION

Aim: to analyze the relationship between circulating anti-HLA antibodies (class-I and class-II), renal pathology and C4d deposition in cases of late acute and chronic antibody-mediated renal allograft rejection according to the method of antibodies detection (ELISA and LUMINEX). Materials and methods. Th e study included 192 patients with indicative graft biopsies (with C4d-staining) and screening detection of anti-HLA antibodies (109 patients by ELISA, 58 patients by LUMINEX, 25 patients – both methods). Patients were divided into 3 groups based on pathology fi ndings: 85 patients with chronic graft rejection, 39 patients with acute antibodymediated rejection (AMR), 68 patients of control group had no signs of AMR. Results. Anti-HLA antibodies (predominantly class-II anti-HLA) were identifi ed in 84.7% of patients with chronic graft rejection, in 84.6% of patients with acute AMR and 33.8% of control group (р &lt; 0.001). Close correlation between the levels of anti￾HLA antibodies detected by different methods was revealed for both classes of antibodies (r² class-I anti-HLA = 0.773, r² class-II anti-HLA = 0.379, р &lt; 0.01). LUMINEX proved to be more sensitive in anti-HLA antibodies detection in all groups. It was especially signifi cant for the diagnosis of C4d-negative acute AMR whose frequen￾cies were 22.2% and 4.8% in detection by LUMINEX and ELISA, respectively (р &lt; 0.01). On the other hand, anti-HLA antibodies being detected by LUMINEX in 55% of patients of the control group more often required determination of donor specifi city. Conclusion. Screening of anti-HLA antibodies (by ELISA and LUMINEX) along with specifi c renal pathology and C4d deposition is suffi cient for the diagnosis of acute and chronic AMR in most cases. Being more sensitive LUMINEX method is preferable for the revealing of C4d-negative AMR, but it requires specifi c DSA detection in many cases.

Acute antibody-mediated rejection in kidney transplant recipients.

Antibody-mediated rejection has now been recognized as one of the most important causes of graft loss. Transplantation across HLA barriers and nonadherence can result in acute antibody-mediated rejection, which is associated with particularly worse graft outcomes. New technologies, including genomic studies and assays to detect and define donor-specific antibodies, have provided important insights into the pathophysiology and diagnosis of acute antibody-mediated rejection but have engendered many questions about the clinical application of these tests in the prognosis and prevention of this protean disease process. In this article, we review the pathophysiology of acute antibody-mediated rejection, the evolving diagnostic criteria, and specific challenges related to its prognosis, treatment, and prevention.

A systematic review of the role of C4d in the diagnosis of acute antibody-mediated rejection

In this study, we conducted a systematic review of the literature to re-evaluate the role of C4d in the diagnosis of acute antibody-mediated rejection of kidney allografts. Electronic databases were searched until September 2013. Eligible studies allowed derivation of diagnostic tables for the performance of C4d by immunofluorescence or immunohistochemistry with comparison to histopathological features of acute antibody-mediated rejection and/or donor-specific antibody (DSA) assays. Of 3492 unique abstracts, 29 studies encompassing 3485 indication and 868 surveillance biopsies were identified. Assessment of C4d by immunofluorescence and immunohistochemistry exhibited slight to moderate agreement with glomerulitis, peritubular capillaritis, solid-phase DSA assays, DSA with glomerulitis, and DSA with peritubular capillaritis. The sensitivity and specificity of C4d varied as a function of C4d and comparator test thresholds. Prognostically, the presence of C4d was associated with inferior allograft survival compared with DSA or histopathology alone. Thus, our findings support the presence of complement-dependent and -independent phenotypes of acute antibody-mediated rejection. Whether the presence of C4d in combination with histopathology or DSA should be considered for the diagnosis of acute antibody-mediated rejection warrants further study.

Correlations of lymphocyte subset infiltrates with donor-specific antibodies and acute antibody-mediated rejection in endomyocardial biopsies.

Acute antibody-mediated rejection (AMR) is a major complication after heart transplantation, posing a significant risk for allograft failure, cardiac allograft vasculopathy, and poor survival. While the inflammatory milieu of cellular rejection and Quilty lesions is well known, the immunologic components of AMR are not well understood. Our aim was to better define the immunophenotype of infiltrating lymphocytes in biopsies with AMR, specifically in relation to donor-specific antibodies to human leukocyte antigen (HLA) class I, II, or both. We performed a retrospective analysis of cardiac transplant patients with concurrent endomyocardial biopsies (EMB), donor-specific antibody (DSA) measurements, and immunofluorescence for C4d at our institution (2005-2011). DSA was evaluated against HLA class I and class II specificities pre- and posttransplant using flow cytometry and/or Luminex bead assays. Acute cellular rejection (ACR) and pathologic AMR (pAMR) were based on the International Society for Heart and Lung Transplantation 2005/2013 reports. Immunohistochemical analysis for CD3, CD4, CD8, and CD79a was performed using standard immunohistochemical protocols on one formalin-fixed, paraffin-embedded EMB from each patient. The number of lymphocytes expressing each protein was enumerated microscopically at 400×. Ratios of T:B cells and CD4:CD8 T cells were then calculated for each EMB. Seventy-nine cardiac transplant patients who had pre- and posttransplant DSA measurements were analyzed. Of these 79 patients, 37 had DSA against HLA class I, HLA class II, or both. Of patients with DSA, the average CD4:CD8 ratio in the EMB was 0.80, while those with only ACR had a CD4:CD8 ratio of 1.49. Interestingly, the T:B cell ratio in patients with and without DSA was 5.7 and 5.5, respectively. Cardiac transplant patients with DSA against HLA have more CD8 cytotoxic T cells than CD4 helper T cells in the EMB lymphocytic infiltrate compared with patients without DSA against HLA. The inflammatory infiltrate T:B cell ratio was similar in patients both with and without DSA. The relative increase of cytotoxic T cells in EMB while the patient has DSA suggests a possible pathogenic role of these cells and may aid in the diagnosis and treatment of AMR.

Diagnosis of Early Pancreas Graft Failure via Antibody-Mediated Rejection: Single-Center Experience With 256 Pancreas Transplantations

Early pancreas graft loss is usually attributed to technical failure while the possibility of antibody-mediated rejection (AMR) is generally overlooked. To investigate the role of AMR in early pancreas graft loss, we retrospectively assessed 256 patients with simultaneous pancreas-kidney transplantation (SPK) between 1985 and 2010 at our institute. We included 33 SPK patients who lost their pancreas graft <1 year after transplantation. AMR was diagnosed based on donor-specific antibodies, C4d and histology in 7 cases, 8 cases were suspicious for AMR and 18 pancreas graft losses were not due to AMR. Acute AMR occurred >1 month after transplantation in 6/7 cases, whereas all other causes typically led to loss <1 month after transplantation. Thrombotic lesions occurred equally among the 33 cases. In 12/18 concurrent kidney specimens, the diagnostic results paralleled those of the pancreas graft. All patients with acute AMR of the pancreas graft lost their renal grafts <1 year after transplantation. In the setting of a thrombotic event, histopathological analysis of early pancreas graft loss is advisable to rule out the possibility of AMR, particularly because a diagnosis of acute AMR has important consequences for renal graft outcomes.

Concurrent Acute Cellular Rejection Is an Independent Risk Factor for Renal Allograft Failure in Patients With C4d-Positive Antibody-Mediated Rejection

Identification of risk factors for renal allograft failure after an episode of acute antibody-mediated rejection (AMR) may help the outcome of this difficult-to-treat complication. During December 2003 to February 2011, 833 kidney graft recipients underwent 1120 clinically indicated biopsies at our center. We reviewed the biopsy results and identified 87 biopsy specimens from 87 patients positive for the degradation product of complement component 4 (C4d) and acute AMR. We generated Kaplan-Meier survival curves and performed a multivariable analysis using the Cox proportional hazards regression model to identify risk factors for allograft failure after C4d+ acute AMR. Among the 87 patients, 26 had a diagnosis of acute AMR according to the Banff '09 classification schema, 29 had acute AMR and chronic active AMR, 18 had acute AMR and acute T-cell mediated rejection (TCMR), and 14 had acute AMR, chronic active AMR, and acute TCMR. Kaplan-Meier survival estimates showed that concurrent acute TCMR (P=0.001, Mantel-Cox log-rank test), concurrent chronic active AMR (P=0.03), and time to biopsy (P=0.04) are associated with graft survival. The Cox proportional hazards regression analysis identified that concurrent acute TCMR (hazard ratio, 2.59 [95% confidence interval, 1.21-5.55]; P=0.01) and estimated glomerular filtration rate (hazard ratio, 0.65 [95% confidence interval, 0.48-0.88]; P=0.01) are independent risk factors for allograft loss. Concurrent chronic active AMR or time to biopsy was not associated with graft failure by the multivariable Cox analysis. Our single-center study has elucidated that concurrent acute TCMR in kidney transplant recipients with C4d+ acute AMR is an independent risk factor for graft failure. Level of allograft function at the time of diagnosis was also an independent predictor of graft loss.

The Diagnosis of Acute Antibody-Mediated Rejection in ABO-Incompatible Liver Transplants

Liver transplantation (LT) across the ABO-blood type barrier is prone to antibody-mediated rejection (AMR), which often leads to a deleterious clinical outcome. While it is of paramount importance to make an early diagnosis of AMR, the morphologic features of AMR in the liver are not specific, and the differential diagnosis is often difficult or even impossible on a morphologic basis alone. The clinical utility of C4d immunostaining is limited in the liver, unlike other organs, further complicating the situation. Therefore, the diagnosis of AMR in the liver requires integration of clinical, morphologic, immunopathologic, and serological evidence.

Acute Antibody-Mediated Rejection of Renal Transplant Associated with Cellular Crescents: First Case Report

Acute antibody-mediated rejection is characterized by histological abnormalities such as glomerulitis, capillaritis, or thrombosis associated with presence of C4d and specific anti-donor antibodies. Reports on the association of glomerular injuries with cellular crescents in antibody-mediated rejection are not found in the literature. We report a unique case of antibody-mediated rejection associated with cellular crescents and suggest that such histological abnormality should be considered in the differential diagnosis of acute antibody-mediated rejection.

Herztransplantation

Since the first heart transplantation in 1967, the procedure has become an established therapy in the treatment of terminal heart failure. Constant advances in the development of potent immunosuppressive drugs, as well as greater clinical experience and pathological diagnostics have improved patient survival dramatically. The first grading system for rejection was published in 1990 by the International Society for Heart and Lung Transplantation (ISHLT) and revised in 2004. The 2004 grading system comprises three grades of severity (1R, 2R, 3R), whereby the former grade 2 in the 1990 system has been incorporated in the new grade 1R. Recommendations are made for the histological diagnosis of acute antibody-mediated rejection using immunohistochemical staining against C4d and macrophages. To the present day, the pathological examination of endomyocardial biopsies remains the gold standard for post-transplant diagnostic procedures. Whether or not non-invasive diagnostic approaches (e.g. gene array profile analysis on leukocytes) can replace morphological investigations needs to be clarified in randomised, prospective clinical studies.

Treatment of Acute Antibody-Mediated Rejection: A Single-Center Experience

Introduction Acute antibody-mediated rejection (AMR) leads to graft loss. The combination of plasmapheresis (PP), intravenous immunoglobulin (IVIG), and rituximab (RTX) has been reported to be effective therapy. Patients and methods Between October 2005 and September 2009, 8 (4.7%) kidney transplant recipients developed AMR, diagnosed by severe acute rejection and extensive C4d staining in peritubular capillaries. Results All patients were treated with two to six sessions of PP with IVIG added after the last PP. In two patients, RTX was prescribed after PP and IVIG. Baseline immunosuppression was based on steroids, mycophenolate mofetil or azathioprine, and tacrolimus or cyclosporine or everolimus. The presence of subsequent significant decrease in anti-HLA class I antibodies was demonstrated in a highly sensitized patient before and after transplantation with PP treatment. An increase was observed before the diagnosis of AMR. After a mean follow-up of 10 months (range = 1–23), patient and graft survivals were 100% and 50%, respectively. Three patients lost their transplants to AMR refractory to treatment and one patient, due to interstitial fibrosis and tubular atrophy at 23 months after AMR. Finally, four patients recovered renal function, showing a mean serum creatinine of 2.2 ± 0.45 mg/dL. Conclusions Early diagnosis and treatment with PP, IVIG, and RTX may resolve AMR. PP before and after transplantation in high-risk patients may result in anti-HLA class I and class II antibody removal from plasma and prevention of AMR.

Specificity and Sensitivity of Screening for Anti-HLA Antibodies in Kidney Allograft Dysfunction

Background Prospective testing for posttransplant circulating anti-HLA antibodies seems to be a critical noninvasive tool, but confirmatory data are lacking. Materials and Methods Over the last 3 years, peritubular capillary (PTC) C4d deposition was prospectively sought by an immunofluorescence technique applied to frozen tissue in biopsies obtained for allograft dysfunction. Screening for circulating anti-HLA class I/II alloantibodies (AlloAb) by the flow cytometric test was performed simultaneously. Results We evaluated 132 sets of biopsies and simultaneous serum samples. PTC C4d deposition was demonstrated in 15.9% (21/132) of biopsies. Circulating anti-HLA I/II AlloAb were detected in 25% (33/132) of serum samples. Employing receiver-operator characteristic (ROC) curves for all C4d-positive biopsies, screening for AlloAb showed a global specificity of 82% and sensitivity of 61.9%. When this analysis was restricted to biopsies obtained in the first month posttransplantation, the sensitivity increased to 81.8%, but the specificity decreased to 76.9%. After the first month posttransplantation, we observed sensitivity of 40.0% and a specificity of 86.4%. In the first month posttransplantation, all patients with a diagnosis of acute antibody-mediated rejection displayed circulating anti-HLA class I/II, but not always at the same time as the C4d-positive biopsy. Conclusions In the first month posttransplantation, prospective monitoring of anti-HLA antibodies may be useful. The high sensitivity allows the identification of patients at risk, affording an earlier diagnosis of antibody-mediated rejection. After the first month, the test can be used to evaluate allograft dysfunction episodes, since positivity is highly suggestive of an antibody-mediated process.

C4d-Positive Interacinar Capillaries Correlates With Donor-Specific Antibody-Mediated Rejection in Pancreas Allografts

The deposition of the complement split fragment C4d and its association with acute antibody-mediated rejection (AMR) in pancreas transplant (PTx) is not well defined. To characterize the deposition of C4d in PTx, we analyzed 27 PTx biopsies from 18 patients transplanted between 2004 and 2007 at the University of Wisconsin. The presence of C4d was graded in interacinar capillaries (IAC), islets, interstitium, and small- and medium-size vessels. Sera obtained at the time or within 5 days of the biopsy were tested for antidonor-specific antibodies (DSA). 16 biopsies (59.26%) showed at least 5% C4d+ IAC (range 5%-90%). Of those, five biopsies (18.5%) revealed diffuse labeling (>50% C4d+ IAC) and 11 (40.74%) showed focal staining (5%-50% C4d+ IAC). C4d+ IAC (>5%) was significantly associated with the presence of strong DSA for class I or class II (P<0.018). C4d staining of the media or endothelium of small and medium-size vessels was a common finding in all biopsies without any association with DSA. Similarly, staining of islets and parenchymal interstitium was not statistically associated with AMR. The majority of patients received intravenous corticosteroid bolus and taper, with specific cases requiring thymoglobulin, IVIg, rituximab, or plasmapheresis. Forty-six percent of patients who demonstrated AMR returned to insulin therapy because of chronic graft damage and loss of C-peptide. Our findings support the potential role of C4d labeling of PTx biopsies in the diagnosis of AMR and emphasize the staining of IAC as a valuable histologic tool for the diagnosis.

Acute Antibody-Mediated Rejection of Renal Transplant: Pathogenetic and Diagnostic Considerations

Acute antibody-mediated rejection (AMR) has emerged recently as an important cause of graft failure. To review the pathogenetic, clinicopathologic, and diagnostic considerations of AMR. Review of literature and the authors' experience. Acute antibody-mediated rejection is mediated by antibodies specific for donor antigens, which bind to target antigens and activate the complement system, culminating in tissue injury. The clinical manifestation of AMR is not specific, and transplant biopsy is needed for diagnosis. The glomeruli show thrombosis or neutrophils or mononuclear leukocytes in capillary lumens. The tubulointerstitial compartment shows edema, hemorrhage, necrosis, mild inflammation, and neutrophils or mononuclear leukocytes in the peritubular capillary lumens. The blood vessels show thrombosis, thrombotic microangiopathy, fibrinoid necrosis, or transmural vasculitis. Strong staining for C4d in the peritubular capillaries is characteristic. A definitive diagnosis of AMR requires (1) morphologic evidence of acute tissue injury, (2) immunopathologic evidence for antibody action, and (3) serologic evidence of circulating donor-specific antibodies. Acute antibody-mediated rejection should be suspected if some but not all 3 criteria are met. Since effective treatment is currently available, accurate and timely diagnosis of AMR is essential.