Acute Rejection In Kidney Transplantation Research Articles

PRINS Long Noncoding RNA Involved in IP-10–Mediated Allograft Rejection in Rat Kidney Transplant

BackgroundPreviously, high levels of CXCR3+ T-cell recruitment was demonstrated in the prolonged ischemia–accelerated acute allograft rejection in rat kidney transplant. In the present study, the effect of chemokine IP-10 was investigated and the expression of chemokine-related PRINS (Psoriasis susceptibility–related RNA gene induced by stress) lncRNA determined in the allografts subjected to ischemia. MethodsF344-to-Lewis rat kidney transplantation was performed, and renal grafts were stored for 2 hours or 16 hours. Samples were removed at 24 hours and 7 days after operation. Cellular infiltration was determined with the use of immunohistochemistry, and messenger RNA expression was assessed with the use of real-time polymerase chain reaction. ResultsThe 16-hour-ischemia kidney displayed acute tubule damage and up-regulation of PRINS lncRNA expression. On day 7, IP-10 expression and CD3-positive T cells were increased in allografts compared with control samples, which were inhibited by the IP-10 antibody treatment accompanied by reduced serum creatinine. ConclusionsThese observations provide evidence for IP-10 in a regulatory role in cold ischemia–elicited acute allograft rejection and in PRINS lncRNA expression. Our data enhance the understanding of the mechanism underlying between prolonged ischemia and acute rejection.

Management of Plasma Cell-Rich Acute Rejection in Living-Related Kidney Transplant: Role of Proteasome Inhibitor.

Plasma cell-rich acute rejection is an aggressive form of acute rejection that occurs late after transplant and is usually resistant to standard antirejection therapy. This study reports the safety, efficacy, and outcomes of plasma cell-rich acute rejection after treatment with bortezomib, a proteasome inhibitor, in 10 patients after a first living-related renal transplant. Plasma cell-rich acute rejection was diagnosed using the 2007 Banff classification. The treatment protocol for plasma cell-rich acute rejection included methylprednisolone (500 mg/kg), 7 sessions of plasmapheresis, antithymocyte globulin (3-5 mg/kg/day for 10 days), rituximab (2 doses at 375 mg/m2), and bortezomib (1 cycle at 1.3 mg/m2). The mean age of recipients and donors was 23.70 ± 11.39 and 37.30 ± 12.82 years, respectively. The mean time to plasma cell-rich acute rejection was 3.1 ± 2.5 years. The mean serum creatinine level at rejection was 4.8 ± 2.7 mg/dL. After treatment, serum creatinine decreased to 3.3 ± 1.8 mg/dL. Serum creatinine levels at 1-year and 2-year follow-up were 3.0 ± 2.3 and 3.3 ± 0.9 mg/dL, respectively. There was 1 graft failure due to recurrence of glomerulonephritis/de novo glomerulonephritis. No significant adverse effects were noted in the patients. Bortezomib successfully reverted plasma cell-rich acute rejection and stabilized graft function, with patients showing 2-year graft survival after rejection of 90%. Bortezomib-based treatment was successful in reverting plasma cell-rich acute rejection and stabilizing graft function, with graft survival of 90% at 2 years. Further studies with large cohorts and randomized trials with or without bortezomib will help in better evaluation of its efficacy, safety, and outcomes.

A biological network-based regularized artificial neural network model for robust phenotype prediction from gene expression data

BackgroundStratification of patient subpopulations that respond favorably to treatment or experience and adverse reaction is an essential step toward development of new personalized therapies and diagnostics. It is currently feasible to generate omic-scale biological measurements for all patients in a study, providing an opportunity for machine learning models to identify molecular markers for disease diagnosis and progression. However, the high variability of genetic background in human populations hampers the reproducibility of omic-scale markers. In this paper, we develop a biological network-based regularized artificial neural network model for prediction of phenotype from transcriptomic measurements in clinical trials. To improve model sparsity and the overall reproducibility of the model, we incorporate regularization for simultaneous shrinkage of gene sets based on active upstream regulatory mechanisms into the model.ResultsWe benchmark our method against various regression, support vector machines and artificial neural network models and demonstrate the ability of our method in predicting the clinical outcomes using clinical trial data on acute rejection in kidney transplantation and response to Infliximab in ulcerative colitis. We show that integration of prior biological knowledge into the classification as developed in this paper, significantly improves the robustness and generalizability of predictions to independent datasets. We provide a Java code of our algorithm along with a parsed version of the STRING DB database.ConclusionIn summary, we present a method for prediction of clinical phenotypes using baseline genome-wide expression data that makes use of prior biological knowledge on gene-regulatory interactions in order to increase robustness and reproducibility of omic-scale markers. The integrated group-wise regularization methods increases the interpretability of biological signatures and gives stable performance estimates across independent test sets.

Genetics of acute rejection after kidney transplantation.

Treatment of acute rejection (AR) following kidney transplantation has improved in recent years, but there are still limitations to successful outcomes. This review article covers literature in regard to recipient and donor genetics of AR kidney and secondarily of liver allografts. Many candidate gene and some genome-wide association studies (GWASs) have been conducted for AR in kidney transplantation. Genetic associations with AR in kidney and liver are mostly weak, and in most cases, the associations have not been reproducible. A limitation in the study of AR is the lack of sufficiently large populations that account for population stratification to study the AR phenotype which in this era occurs in <10% of transplants. Furthermore, the AR phenotype has been difficult to define and the definitions of classifications have evolved over time. Literature related to the pharmacogenomics of tacrolimus is robust and has been validated in many studies. Associations between gene expression and AR are emerging as markers of outcomes and AR classification. In the future, combinations of pretransplant genotype for AR risk prediction, genotype-based immune suppressant dosing, and pharmacogenomic markers to select AR maintenance or treatment and expression markers from biopsies may provide valuable clinical tools for guiding treatment.

Prevalence, causes, and complications of acute kidney transplant rejection: survey in a single center

Backgrounds: Kidney transplantation has become a preferred surgical approach for several renal disorders. To acquire required information in basis of acute transplant rejection and its complications, it is important to determine rejection prevalence and its potential causes.Methods: In present retrospective study, during a 37-year survey, 2250 patients received conventional kidney transplantation. The patients who had suffered graft loss, death, and nephrectomy of transplanted kidney during the first month after transplantation enrolled the study and all required data recorded in designed questionnaire. Results: Of 2557 patients underwent kidney transplantation, 86 (3.36%) patients were suffered acute graft loss during the first month after transplantation, that 43 (50%) were males and 43 (50%) were females. Mean age of the patients with acute graft loss was 40.09±14.09. The most common underlying cause for acute graft loss in our study were as follows: acute rejection of transplanted kidney (34.9%), renal vein thrombosis (17.5%), heart infarction (13.9%), idiopathic (6.9%). Of 86 patients, thirty-three patients underwent nephrectomy subsequent to rejection, however, fifty-three patients well responded to medical treatment. In our study the amount of acute nephrectomy during the first month after transplantation was 38.4% (33 patients) which constituted 1.2% of the total graft losses.Conclusion: Renal vein thrombosis is the most common underlying reason for graft loss in kidney transplantation patients, and 1st week of the transplantation is the most probable postoperative time for graft rejection.

Management of End Stage Renal Disease in Persons Living with HIV: A Cost-Effectiveness Analysis

BackgroundHIV+ kidney transplant (KT) for persons living with HIV (PLWH) is both safe and effective, with comparable patient and graft survival rates relative to HIV- KT. The objective of this study was to evaluate the cost-effectiveness of HIV+ KT relative to HIV- KT and dialysis.MethodsA decision-tree framework was used to assess the cost-effectiveness of the above treatment options for PLWH. Clinical outcomes at 3 years for KT and effectiveness data (expressed in QALYs) were abstracted from previous publications, when available. Costs were assigned from a payer’s perspective using the US Renal Data System and published literature (expressed in 2014 USD). This analysis assumed a three-year time horizon. Sensitivity analyses were explored to understand how changes in 1) acute KT rejection and 2) KT failure impact cost effectiveness. Limitations include small sample size and short follow up time in referenced studies and a lack of health utility data in HIV positive persons with renal failure. We used TreeAge Software (Williamstown, MA).ResultsHIV+ KT was most cost effective ($299,904/QALY) while both HIV- KT ($329,676) and dialysis ($444,645) were dominated, meaning more costly and less effective. Results were sensitive to the higher KT failure (26% vs. 16%) and acute rejection (39% vs. 17%) observed with HIV- KT relative to HIV+ KT. In sensitivity analysis, as HIV+ KT rejection rates approach 20%, HIV- KT becomes a cost-effective option. As HIV+ KT failure rates approach 26%, HIV- KT becomes cost effective.ConclusionDespite its limitations, this analysis demonstrates that HIV+ kidney transplantation is a cost-effective alternative for PLWH under certain conditions. As KT outcomes, like graft failure and acute rejection rates, continue to improve, it is likely that both HIV positive and negative KT will be cost-effective alternatives to dialysis.Disclosures All authors: No reported disclosures.

Acute Rejection After Kidney Transplantation Associates With Circulating MicroRNAs and Vascular Injury.

Acute rejection (AR) of kidney transplants is associated with the loss of endothelial integrity, microvascular rarefaction and, ultimately, graft dysfunction. Circulating angiogenic microRNAs (miRNAs) may serve as markers for microvascular injury. Here, we investigated the short- and long-term effects of AR after kidney transplantation on systemic vascular injury and the associated circulating miRNA profile. Systemic vascular injury was determined by measuring capillary tortuosity and density within the oral mucosa as well as by assessing circulating levels of angiopoietin-2/angiopoietin-1 ratio, vascular endothelial growth factor and soluble thrombomodulin. After a pilot study, we selected 48 miRNAs to assess the AR- and microvascular injury associated circulating miRNAs. In stable transplant recipients (n = 25) and patients with AR (n = 13), which were also studied longitudinally (1, 6, and 12 months post-AR), we found an AR-associated increase in markers of systemic vascular injury, of which vascular endothelial growth factor and soluble thrombomodulin normalized within 1 year after AR. Of the 48 selected miRNAs, 8 were either decreased (miR-135a, miR-199a-3p, and miR-15a) or increased (miR-17, miR-140-3p, miR-130b, miR-122 and miR-192) in AR. Of these, miR-130b, miR-199a, and miR-192 associated with markers of vascular injury, whereas miR-140-3p, miR-130b, miR-122, and miR-192 normalized within 1 year after AR. AR after kidney transplantation is characterized by systemic microvascular injury and associates with specific circulating miRNA levels.

Biomarkers to detect rejection after kidney transplantation.

Detecting acute rejection in kidney transplantation has been traditionally done using histological analysis of invasive allograft biopsies, but this method carries a risk and is not perfect. Transplant professionals have been working to develop more accurate or less invasive biomarkers that can predict acute rejection or subsequent worse allograft survival. These biomarkers can use tissue, blood or urine as a source. They can comprise individual molecules or panels, singly or in combination, across different components or pathways of the immune system. This review highlights the most recent evidence for biomarker efficacy, especially from multicenter trials.

A model of acute renal allograft rejection in outbred Yorkshire piglets

Pigs represent a desirable animal model for the study of rejection in kidney transplantation with inbred Yucatan miniature swine (YMS) the most commonly studied strain due to well defined swine leukocyte antigen (SLA) genotypes. However, limitations to YMS may include cost and availability. Outbred Yorkshire pigs are widely available and significantly cheaper than YMS. Recent advances in SLA genotyping have allowed its application to outbred strains. On this basis, we theorized that Yorkshire pigs would be a viable alternative to YMS for the study of rejection in kidney transplantation. To address this question, we performed auto (Auto) and allotransplants (Allo) in 24 Yorkshire pigs, and assessed SLA genotypes and acute rejection after 72h. At sacrifice, and when compared to autotransplants, allotransplants had significant elevations in serum creatinine (8.4±1.3 vs 2.8±2.0mg/dL for Allo vs autotransplants, respectively) and BUN (61±9 vs 19.2±15mg/dL for Allo vs autotransplants, respectively). Warm ischemia times between the two groups did not differ (24±2.3 vs 26.4±1.4min for Auto vs Allo, respectively). There were 16 distinct SLA haplotypes identified from pigs undergoing allotransplantion, no matched donor-recipient pairs, and all allografts demonstrated rejection. Type IIA cellular rejection (Banff) was the most common. One allograft demonstrated hyperacute rejection due a blood group incompatibility. Histologically, the expression of regulatory Tcells and dendritic cells was increased in allografts. These data suggest that Yorkshire pigs may be a useful model for the study of acute rejection in experimental kidney transplantation.

Association Between TLR2, TLR4, and CD14 Gene Polymorphisms and Acute Rejection in Kidney Transplant.

Toll-like receptors play an important role in innate and adaptive immune responses and can induce acute graft rejection, especially in the early phase after transplant. The aim of this study was to evaluate the possible association between TLR2, TLR4, and CD14 polymorphisms and acute renal rejection. Our study included 239 patients seen between 2013 and 2015. Patients were classified into 3 groups: acute rejection group (71 patients), stable graft function group (71 patients), and healthy control group (97 patients). Polymorphisms in TLR2 (Arg753Gln, rs5743708), TLR4 (Asp299Gly, rs4986790; Thr399Ile, rs4986791), and CD14 (-159C/T, rs2569190) were determined by the TaqMan allelic discrimination assay for detection of single-nucleotide polymorphisms. The genotype distribution of CD14 rs2569190C/T was found to be significantly different among the acute rejection, stable graft function, and healthy control groups (P < .05). Interestingly, based on logistic regression, CD14 genotype (rs2569190) in patients with acute rejection was still significant after including risk factors. The adjusted odds ratio for CD14 CT+TT over CC genotype was calculated as 3.172 (95% confidence interval, 1.397-7.200; P = .006). Moreover, incidence of acute rejection and graft loss were significantly more frequent in recipients carrying CD14 TT (95% confidence interval, 2.81-27.16; P ≤ .001). In contrast to CD14, no significant differences were observed in the single-nucleotide polymorphisms of TLR2 and TLR4 genes in the acute rejection group versus the stable graft function and healthy control groups. The presence of CD14 T allele was associated with a significantly lower rejection-free survival compared with the CD14 CT and CC genotypes (P ≤ .001). Renal transplant recipients carrying the CD14-159 TT genotype have significantly higher risk of acute rejection and reduced transplant survival rate than patients with heterozygous or wild-type genotypes.

Evaluation of Digital PCR as a Technique for Monitoring Acute Rejection in Kidney Transplantation.

Early detection and proper management of kidney rejection are crucial for the long-term health of a transplant recipient. Recipients are normally monitored by serum creatinine measurement and sometimes with graft biopsies. Donor-derived cell-free deoxyribonucleic acid (cfDNA) in the recipient's plasma and/or urine may be a better indicator of acute rejection. We evaluated digital PCR (dPCR) as a system for monitoring graft status using single nucleotide polymorphism (SNP)-based detection of donor DNA in plasma or urine. We compared the detection abilities of the QX200, RainDrop, and QuantStudio 3D dPCR systems. The QX200 was the most accurate and sensitive. Plasma and/or urine samples were isolated from 34 kidney recipients at multiple time points after transplantation, and analyzed by dPCR using the QX200. We found that donor DNA was almost undetectable in plasma DNA samples, whereas a high percentage of donor DNA was measured in urine DNA samples, indicating that urine is a good source of cfDNA for patient monitoring. We found that at least 24% of the highly polymorphic SNPs used to identify individuals could also identify donor cfDNA in transplant patient samples. Our results further showed that autosomal, sex-specific, and mitochondrial SNPs were suitable markers for identifying donor cfDNA. Finally, we found that donor-derived cfDNA measurement by dPCR was not sufficient to predict a patient's clinical condition. Our results indicate that donor-derived cfDNA is not an accurate predictor of kidney status in kidney transplant patients.

The Risk of Acute Rejection Following Kidney Transplant by 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Status: A Prospective Cohort Study.

Background:Prediction of acute kidney transplant rejection remains imperfect despite several known risk factors. There is an increasing appreciation of the potential importance of the vitamin D pathway in immunological disease and transplantation.Objective:The purpose of this study was to determine the association of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D with acute rejection.Design:This was a prospective cohort study.Setting:Three academic adult kidney transplant programs in Ontario, Canada, were chosen.Patients:All consecutive adult patients at the 3 institutions who received a solitary kidney transplant, were able to provide written informed consent, and planned to be followed at the same center post-operatively were included.Measurements:Serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured at baseline, 3, and 6 months post-transplantation. Acute rejection was classified using Banff criteria.Methods:The co-primary outcome was the association between 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D and time to first occurrence of biopsy-proven acute rejection (BPAR) within the first year after kidney transplantation. Cox proportional hazards models were fitted taking into account the time-varying nature of serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D.Results:From 556 screened patients, data on 327 kidney transplant recipients are included. First BPAR occurred in 54 (16.5%) patients. In adjusted Cox proportional hazards models, the serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D was not associated with acute renal transplant rejection (hazard ratio 1.00; 95% [confidence interval] CI, 0.87-1.14, per 10 nmol/L increase, and hazard ratio 0.97; 95% CI, 0.84-1.12, per 10 pmol/L increase, respectively).Limitations:Given the observational design, we cannot rule out the possibility of residual confounding that limited our ability to detect a clinically significant effect of vitamin D metabolites on acute rejection.Conclusions:A low serum concentration of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D is not associated with an increased risk of acute kidney transplant rejection following kidney transplantation.

The Association Between Broad Antigen HLA Mismatches, Eplet HLA Mismatches and Acute Rejection After Kidney Transplantation.

Epitope matching, which evaluates mismatched amino acids within antigen-antibody interaction sites (eplets), may better predict acute rejection than broad antigen matching alone. We aimed to determine the association between eplet mismatches and acute rejection in kidney transplant recipients. The association between eplet mismatches, broad antigen mismatches and acute rejection was assessed using adjusted Cox proportional hazard regression. Model discrimination for acute rejection was evaluated using the area under receiver operating characteristic curves. Of the 3,499 kidney transplant recipients from 2006 to 2011, the average (SD) number of broad antigen and eplet mismatches were 3.4 (1.7) and 22.8 (12.2), respectively. Compared with 0 to 2 eplet mismatches, the adjusted hazard ratio (HR) for acute rejection among those with 20 or greater eplet mismatches was 2.16 (95% confidence interval [CI], 1.33-3.52; P = 0.001). The adjusted area under the curve for broad antigen mismatches was 0.58 (95% CI, 0.56-0.61), similar to that for eplet mismatches (HR, 0.59; 95% CI, 0.56-0.61; P = 0.365). In recipients who were considered as low immunological risk (0-2 broad antigen HLA-ABDR mismatch), those with 20 or greater eplet mismatches experienced an increased risk of rejection compared to those with less than 20 mismatches (adjusted HR, 1.85; 95% CI, 1.11-3.08; P = 0.019). Increasing number of eplet mismatches is associated with acute rejection in kidney transplant recipients. Consideration of eplet HLA mismatches may improve risk stratification for acute rejection in a selected group of kidney transplant candidates.

Profiling risk for acute rejection in kidney transplantation: recipient age is a robust risk factor.

Careful management of immunosuppression is paramount to prevent acute rejection in kidney transplantation. We studied a cohort of 139,875 kidney transplant recipients from the Organ Procurement and Transplantation Network (OPTN) database between 2002 and 2013. We confirmed the analysis with a cohort of 35,277 who received thymoglobulin induction with tacrolimus maintenance, and a third cohort of 12,161 recipients who received basiliximab induction with tacrolimus maintenance. We performed multivariate logistic regression analyses on data from all three cohorts and identified independent risk factors for treated acute rejection at 1year. Recipient age was a robust risk factor for rejection in all three cohorts in a dose response pattern. Young age (18-25years) was among the strongest risk factors for rejection in all three cohorts; thymoglobulin cohort: OR 1.87 (1.59-2.19); basiliximab cohort: OR 2.41 (1.89-3.05); and inclusive cohort: OR 1.97 (1.83-2.12). The opposite was true for old age (65-69years); thymoglobulin cohort: OR 0.69 (0.59-0.81); basiliximab cohort: OR 0.77 (0.62-0.96); and inclusive cohort: OR 0.75 (0.70-0.80). This study is unique because it is the largest and most comprehensive multivariate analysis that demonstrates recipient age is a robust risk factor for acute rejection in an inverse dose response pattern.

Successful Salvage Treatment of Resistant Acute Antibody-Mediated Kidney Transplant Rejection with Eculizumab.

Antibody-mediated rejection (ABMR) jeopardises short- and long-term transplant survival and remains a challenge in the field of organ transplantation. We report the first use of the anticomplement agent eculizumab in Oman in the treatment of a 61-year-old female patient with ABMR following a living unrelated kidney transplant. The patient was admitted to the Sultan Qaboos University Hospital in Muscat, Oman, in 2013 on the eighth day post-transplantation with serum creatinine (Cr) levels of 400 µmol/L which continued to rise, necessitating haemodialysis. A biopsy indicated ABMR with acute cellular rejection. No improvement was observed following standard ABMR treatment and she continued to require dialysis. Five doses of eculizumab were administered over six weeks with a subsequent dramatic improvement in renal function. The patient became dialysis-free with serum Cr levels of 119 µmol/L within four months. This case report indicates that eculizumab is a promising agent in the treatment of ABMR.

Acute Kidney Injury: Not Just an Acute Rejection in Kidney Transplantation

Acute Kidney Injury: Not Just an Acute Rejection in Kidney Transplantation

Clinically-relevant threshold of preformed donor-specific anti-HLA antibodies in kidney transplantation

BackgroundPretransplant anti-HLA donor-specific antibodies (DSA) are recognized as a risk factor for acute antibody-mediated rejection (AMR) in kidney transplantation. The predictive value of C4d-fixing capability by DSA or of IgG DSA subclasses for acute AMR in the pretransplant setting has been recently studied. In addition DSA strength assessed by mean fluorescence intensity (MFI) may improve risk stratification. We aimed to analyze the relevance of preformed DSA and of DSA MFI values. Methods280 consecutive patients with negative complement-dependent cytotoxicity crossmatches received a kidney transplant between 01/2008 and 03/2014. Sera were screened for the presence of DSA with a solid-phase assays on a Luminex flow analyzer, and the results were correlated with biopsy-proven acute AMR in the first year and survival. ResultsPretransplant anti-HLA antibodies were present in 72 patients (25.7%) and 24 (8.6%) had DSA. There were 46 (16.4%) acute rejection episodes, 32 (11.4%) being cellular and 14 (5.0%) AMR. The incidence of acute AMR was higher in patients with pretransplant DSA (41.7%) than in those without (1.6%) (p<0.001). The median cumulative MFI (cMFI) of the group DSA+/AMR+ was 5680 vs 2208 in DSA+/AMR− (p=0.058). With univariate logistic regression a threshold value of 5280 cMFI was predictive for acute AMR. DSA cMFI’s ability to predict AMR was also explored by ROC analysis. AUC was 0.728 and the best threshold was a cMFI of 4340. Importantly pretransplant DSA>5280 cMFI had a detrimental effect on 5-year graft survival. ConclusionsPreformed DSA cMFI values were clinically-relevant for the prediction of acute AMR and graft survival in kidney transplantation. A threshold of 4300–5300 cMFI was a significant outcome predictor.

Acute Antibody-Mediated Rejection in Kidney Transplant Based on the 2013 Banff Criteria: Single-Center Experience in Uruguay

BackgroundAcute antibody-mediated rejection (AMR) diagnosis criteria have changed in recent consensus of Banff, with current evidence of C4d-negative AMR. Our objective was to evaluate incidence of AMR in renal transplantation according to Banff 2013 criteria and to examine the histological features and outcome. MethodsThis retrospective study involved all kidney transplants with histological diagnosis of acute rejection (AR) at our center between 2000 and 2014. All the biopsies with AR were re-assessed by a nephro-pathologist and classified by use of the Banff 2013 criteria. ResultsOf 205 kidney transplants, biopsy-proven AR was diagnosed in 25 cases (12%). Re-assessing them according to Banff 2013 criteria, AMR was diagnosed in 17 (8.3%) and represented 68% of the confirmed rejections. AMR diagnosis was performed on day 23 ± 26, with median of 11 days. From the 17 cases, 7 had concomitant T-cell–mediated rejection. All cases presented endothelial edema and acute tubular necrosis. Glomerulitis was found in 12 cases and capillaritis in 14. In 3, associated thrombotic micro-angiopathy (TMA) was found. Intimal and transmural arteritis was evidenced in 5 and 1 patient. In 2, transplant glomerulopathy was present. Seven of the 10 biopsies with C4d staining in the peri-tubular capillaries were positive. Twelve cases received plasmapheresis, 6 received gamma-globulin, and 6 received rituximab. After administration of anti-AMR therapy, 16 cases recovered renal function, reaching a serum creatinine level of 1.5 ± 0.6 mg %. Graft survival at 1 year was lower in the AMR group versus patients without AMR (81.9% vs 98.9%, log-rank test, P < .001). Risk factors for AMR were re-transplant (30% vs 7%, P = .02), HLA-DR mismatch (1.06 ± 0.65 vs 0.7 ± 0.6, P = .03), panel-reactive antibody (28% ± 33 vs 6.2 ± 13, P = .00), and delayed graft function (82% vs 30%, P = .00). ConclusionsAdapting the new Banff 2013 criteria increased the sensitivity of the diagnosis of ARM. Regarding our data, despite an adequate response to the therapy, it resulted in a worse graft survival by the first year of renal transplant.

The Challenge of Acute Antibody-Mediated Rejection in Kidney Transplantation.

The Challenge of Acute Antibody-Mediated Rejection in Kidney Transplantation.

Compartment-specific expression of natural killer cell markers in renal transplantation: immune profile in acute rejection.

Natural killer (NK) cells have been implicated in graft dysfunction. Here, we formulated hypothesis that distinct patterns of expression NK cells markers correlated with acute rejection in kidney transplantation. Therefore, we studied the pattern of NK cell markers CD56, CD57, and CD16 in different compartments of biopsies obtained from recipients diagnosed with acute graft rejection, with or without donor-specific antibodies (DSA). DSA-negative biopsies-from patients with acute T-cell mediated rejection (aTCMR) had an increased expression of CD56+ and CD57+ cells (P = 0.004 and P = 0.001) in the interstitial compartment in comparison with DSA-positive biopsies from patients acute antibody-mediated rejection (aABMR) with (aABMR C4d+) and without C4d deposition (aABMR C4d-). CD16+ cells was increased (P = 0.03) in the glomerular compartment in DSA-positive biopsies. We assume that CD16+ expression and antibody-dependent cellular cytotoxicity (ADCC) in microvascular injury can be associated with aABMR. IFN-γ release from cytoplasmic granules of NK cell could be associated with aTCMR. Our findings suggest that NK cells need to be carefully evaluated because variations in NK cell marker expression might imply the involvement of different immune system pathways in graft rejection.