Marker Of Rejection Research Articles

Role of pericoronary adipose tissue inflammation at CCTA after heart transplantation as non-invasive diagnostic tool of cardiac rejection and predictor of major adverse cardiovascular events

Abstract Background Long-term survival of heart transplanted (HT) patients is challenged by cardiac rejection and cardiac allograft vasculopathy (CAV). Until now, there are no established biomarkers for graft dysfunction, and the conventional approach for cardiac rejection surveillance is through the endomyocardial biopsy (EMB), an invasive and costly procedure. Purpose This study investigates the prognostic value of the pericoronary Fat Attenuation Index (FAI) and its role as a marker of inflammation and rejection in HT recipients. Methods A double-center observational retrospective study was conducted on a cohort of HT patients who underwent coronary computed tomography angiography (CCTA) between January 2016 and December 2022. FAI was measured with dedicated software and using the cut-off described in literature, we considered each coronary as "inflamed" if FAI was ≥ - 70,1 HU and "not inflamed" if FAI was < - 70,1 HU. Then, based on the number of inflamed coronary arteries for each patient, we divided the population into two comparison groups: high inflammatory (high INF) phenotype (alle three coronary arteries inflamed) and low inflammatory (low INF) phenotype (at least one coronary artery not inflamed). The primary endpoint was a composite of all-cause mortality, acute myocardial infarction, urgent revascularization and heart failure hospitalization. Furthermore, we investigated the correlation between FAI and cardiac rejection by looking for T cell-mediated rejection (TCMR) and antibody-mediated rejection (AMR) through EMB performed no more than six months before or after CCTA. Results A total of 101 HT patients were included; of this group 58 patients underwent EMBs within six months after or before the CCTA. The median duration of follow-up was 28 months. The composite endpoint occurred in 17 patients (16.8%). We documented 26 significative cardiac rejection episodes, 14 TCMR ≥ 2R and 12 AMR. The composite endpoint was achieved in 37.9% of patients with high INF phenotype compared to 8.3% with low INF phenotype (p < 0.001). In the multivariate analysis, the high INF phenotype remained an independent predictor of the composite endpoint in our population (HR: 10.5; 95% CI: 1.88-58.71; p = 0.007). Patients with TCMR and AMR had significantly higher FAI values. High INF phenotype correlated with the presence of ACR ≥ 2R (55.0% vs 7.9%, p < 0.001) and AMR (55.0% vs 2.6%, p < 0.001). Conclusion In HT patients, FAI is an independent predictor of major cardiovascular events. It is also associated with TCMR and AMR within six months from CCTA. FAI, therefore, may offer a non-invasive approach to stratify the prognosis of HT patients and serve as a valuable inflammatory biomarker for early diagnosis of cardiac rejection, supporting the use of CCTA in this setting of patients.Correlation FAI and MACECorrelation FAI and cardiac rejection

Volatile organic compound profile for the search of rejection markers in protein baits used as Vespa velutina control method

The invasive species Vespa velutina nigrithorax (Lepeletier 1836), commonly known as the Asian hornet, constitutes an economic and environmental threat, as it is a predator of fruits and insects, especially Apis mellifera (Linnaeus, 1758) (honey bees).Different methods have been developed for its control. Among of them, biocidal protein baits are included, which have a limited time of use. Oxidation of their components, enzymatic activity and microorganisms lead to the formation of spoilage compounds.The aim of this work was to determine the optimal conditions for storing and preserving the baits without losing efficacy. Furthermore, a search of rejection markers will be carried out based on field studies results in the apiary on the acceptance and rejection of the baits by hornets under different storage conditions.Volatile organic compound profiles of these baits were obtained by solid phase microextraction/gas chromatography/mass spectrometry (SPME-GC–MS). The data were processed using different statistical and chemometric tools.The identification of potential rejection markers belonging to the families of ketones, esters, alcohols and amines was carried out by partial least squares discriminant analysis (PLS-DA). The four markers with the highest VIP scores were 2-butanone, 2-heptanone, 1-butanol, 3-methyl and 1-butanol, 3-methyl, acetate.

Discourse markers of rejection in three varieties of Spanish

In the study of discourse markers in Spanish, a field with great vitality in the last few decades, it is common to overlook the expressions used to accept or reject a proposal, suggestion or petition, often included within the broader functions of agreement and disagreement. These answers, used in an informal oral interactive context, exhibit a rich dialectal variety. Due to the fleeting nature of their contexts of use, they are difficult to formally register for further study, especially when looking at them from a panhispanic perspective. For this reason, an anonymous survey was designed in order to ask native speakers about their familiarity with a series of discourse markers used to answer “no” to a proposal. The questionnaire was disseminated in the countries of Spain, Mexico and Colombia, specifically around the capital areas. Participants (N=223) evaluated from 1 (I do not know this expression) to 5 (I use this expression frequently) a series of possible responses, and they were offered the option to provide some other answers not included in the original list. Results show that, while some discourse markers are used to a certain degree in the three varieties, others are prototypical from one of these dialects. The opportunity to offer new expressions was very productive, especially in the case of participants from Colombia and Mexico. While this study focuses on three particular regions, it opens the door to a comparative analysis of discourse markers of negation throughout the Spanish speaking world.

Gene expression–based molecular scoring of pancreas transplant rejection for a quantitative assessment of rejection severity and resistance to treatment

Pancreas transplantation improves glycemic control and mortality in patients with diabetes but requires aggressive immunosuppression to control the alloimmune and autoimmune response. Recent developments in “omics” methods have provided gene transcript-based biomarkers for organ transplant rejection. The tissue Common Response Module (tCRM) score is developed to identify the severity of rejection in kidney, heart, liver, and lung transplants. Still, it has not yet been validated in pancreas transplants (PT). We evaluated the tCRM score’s relevance in PT and additional markers of acute cellular rejection (ACR) for PT. An analysis of 51 pancreas biopsies with ACR identified 37 genes and 56 genes significantly upregulated in the case of grade 3 and grade 2 ACR, respectively (P < .05). Significant differences were seen with higher grades of rejection among several transcripts. Of the 22 genes differentially expressed in grade 3 ACR, 18 were also differentially expressed in grade 2 ACR. The rejection signal was attributable to activated leukocytes’ infiltration. Significantly higher tCRM scores were found in grade 3 ACR (P = .007) and grade 2 ACR (P = .004), compared to normal samples. The tCRM score was able to distinguish treatment-resistant cases from those successfully treated for rejection.

Immune Rejection Mediated by prf1 and gzmb Affects the Colonization of Fat Greenling (Hexagrammos otakii) Spermatogonia in Heterotransplantation.

Fish germ cell transplantation holds great potential for conserving endangered species, improving cultured fish breeds, and exploring reproductive techniques. However, low transplantation efficiency is a common issue in heterotransplantation. This study transplanted fat greenling (Hexagrammos otakii) spermatogonia into the testes of spotted sea bass (Lateolabrax maculatus) to investigate factors that might affect the colonization and fixation of heterologous transplanted germ cells. Results indicated that transplanted fat greenling spermatogonia cells were successfully detected in the early transplantation phase in spotted sea bass. Their numbers gradually decreased over time, and after 10 days post-transplantation, more than 90% of the transplanted cells underwent apoptosis. Transcriptome sequencing analysis of the testes of spotted sea bass and fat greenling spermatogonia on days 1 and 10 post-transplantation revealed that this apoptosis process involved many immune-related genes and their associated signaling pathways. Acute immune rejection marker genes prf1 and gzmb were detected in the spotted sea bass testes, while immune tolerance genes lck and zap-70 were expressed in the fat greenling spermatogonia. Additionally, differential expression of prf1 and gzmb genes was screened from spotted sea bass, with experimental evidence indicating that PRF1 and GZMB protein from spotted sea bass primarily induce apoptosis in transplanted fat greenling spermatogonia via the mitochondrial apoptosis pathway, at the protein level. This suggests that the difficulties in heterotransplantation are primarily related to acute immune rejection, with PRF1 and GZMB playing significant roles.

Extracellular vesicles as potential diagnostic markers for kidney allograft rejection.

Kidney transplantation is a highly effective treatment for end-stage kidney disease. However, allograft rejection remains a significant clinical challenge in kidney transplant patients. Although kidney allograft biopsy is the gold-standard diagnostic method, it is an invasive procedure. Since the current monitoring methods, including screening of serum creatinine and urinary protein, are not of sufficient sensitivity, there is a need for effective post-transplant monitoring to detect allograft rejection at an early stage. Extracellular vesicles are vesicles with a lipid bilayer that originate from different cell types in pathological and physiological conditions. The content of extracellular vesicles reflects the status of cells at the time of their production. This review comprehensively summarizes clinical, in vivo, and in vitro reports that highlight the potential of extracellular vesicles as diagnostic biomarkers for kidney allograft rejection. Clarification would facilitate differentiation between rejection and non-rejection and identification of the mechanisms involved in the allograft rejection. Despite increasing evidence, further research is necessary to establish the clinical utility of extracellular vesicles in the diagnosis and monitoring of allograft rejection in kidney transplant recipients. Using extracellular vesicles as non-invasive biomarkers for diagnosis of kidney allograft rejection could have tremendous benefits in improving patient outcomes and reduce the need for invasive procedures.

(361) - Soluble Immune Check Point Receptors Could be Feasible Markers of Rejection in Lung Transplanted Patients?

(361) - Soluble Immune Check Point Receptors Could be Feasible Markers of Rejection in Lung Transplanted Patients?

Association Between High Sensitivity Troponin Levels Following Pediatric Orthotopic Heart Transplantation and Intensive Care Unit Resource Utilization.

The utility of troponin levels, including high sensitivity troponin T (hs-TnT), after orthotopic heart transplant (OHT) is controversial. Conflicting data exist regarding its use as a marker of acute rejection. Few studies have examined possible associations of hs-TnT levels immediately after OHT with metrics of intensive care unit (ICU) resource utilization or risk of acute rejection. We performed a retrospective cohort chart review including all OHT recipients < 20years of age at our center between June 2019 and December 2022. Patients were divided into two groups based on supra- or sub-median initial hs-TnT levels (median 3462.5ng/L). Primary outcome was days requiring ICU-level care, secondary outcomes included days intubated, days requiring positive pressure ventilation (PPV), days on inotropic medications, actual ICU length of stay, Vasoactive Inotrope Scores (VIS) on postoperative days (POD) 0 through 7, and acute rejection at 30days and one year after OHT. Patients with higher hs-TnT required ICU level care for longer [13.5 (10-17.5) vs. 9.5 (8-12) days, p = 0.01] and spent more days intubated [6 (4-7) vs. 3 (3-5) days, p < 0.001], on PPV [9 (6-15) vs. 6 (5-8.5) days, p = 0.02], and on inotropes [11 (9-14) vs. 8 (7-11) days, p = 0.025]. VIS was only different between groups on POD7 [5 (3-7) vs. 3 (0-5), p = 0.04]. There was no difference in rejection between the groups. Higher hs-TnT immediately following pediatric OHT may predict higher ICU resource utilization, despite no difference in VIS, although it does not predict acute rejection in the first year after OHT.

Donor-derived cell-free DNA as a diagnostic marker for kidney-allograft rejection: A systematic review and meta-analysis.

Donor-derived cell-free DNA (dd-cfDNA) has emerged as a promising biomarker for detecting graft rejection. This study aimed to evaluate the diagnostic accuracy and clinical value of applying it to kidney transplant rejection. Relevant literature on dd-cfDNA diagnostics in kidney transplant rejection was reviewed from PubMed, Embase, Cochrane Library, and Web of Science databases up to 2023. Data and study characteristics were extracted independently by two researchers, and disagreements were resolved through discussion. Diagnostic accuracy data for any rejection (AR) and antibody-mediated rejection (ABMR) were analyzed separately. Potential heterogeneity was analyzed by subgroup analysis or meta-regression. Funnel plots were used to clarify the presence or absence of publication bias. Nine publications provided data on dd-cfDNA accuracy in diagnosing patients with AR. The pooled sensitivity, specificity, and the area under the receiver operating characteristic (AUROC) curve with 95% confidence intervals (CI) were 0.59 (95% CI, 0.48-0.69), 0.83 (95% CI, 0.76-0.88), and 0.80 (95% CI, 0.76-0.83), respectively. Additionally, 12 studies focused on the diagnostic accuracy of dd-cfDNA for ABMR, showing pooled sensitivity, specificity, and the AUROC curve with 95% CI of 0.81 (95% CI, 0.72-0.88), 0.80 (95% CI, 0.73-0.86), and 0.87 (95% CI, 0.84-0.90), respectively. Study type, age group, and sample size contributed to heterogeneity. In summary, our findings indicate that while plasma dd-cfDNA accuracy in diagnosing patients with AR is limited by significant heterogeneity, it is a valuable biomarker for diagnosing ABMR.

Extracorporeal Photopheresis Reduces Fibrotic and Inflammatory Transcriptomic Biological Marker of Chronic Antibody-mediated Kidney Rejection.

The benefit of extracorporeal photopheresis on the course of kidney transplant rejection is unknown. The aim of our study was to investigate the variations in transcriptomics on graft biopsies when extracorporeal photopheresis was used to treat chronic humoral rejection after kidney transplantation. We retrospectively analyzed the mRNA expression of 770 genes of interest in graft biopsies performed before and after treatment. Eight patients received an average of 23 extracorporeal photopheresis sessions over 4 mo between the 2 biopsies. Transcriptomic analysis of the graft biopsies identified a significant (adjusted P < 0.05) increase in CAV1 mRNA in all patients and a significant decrease in CD19, IL21, PAX5, and SFTPA2 mRNAs in 7 of 8 patients. In patients treated with extracorporeal photopheresis for chronic humoral rejection after renal transplantation, omic analysis of repeated biopsies shows a reduction in fibrotic and inflammatory transcriptomic biologicals markers.

Levels of Cell-Free DNA in Kidney Failure Patients before and after Renal Transplantation.

Circulating cell-free DNA (cfDNA) has diverse applications in oncological, prenatal, toxicological, cardiovascular, and autoimmune diseases, diagnostics, and organ transplantation. In particular, mitochondrial cfDNA (mt-cfDNA) is associated with inflammation and linked to early vascular ageing (EVA) in end-stage kidney failure (ESKF), which could be a noninvasive marker for graft rejection and organ damage. Plasma samples from 44 ESKF patients, of whom half (n = 22) underwent either conservative therapy (non-HD) or hemodialysis (HD) before kidney transplantation (KT). These samples were analyzed at baseline and two years after KT. cfDNA was extracted from plasma and quantified using the fluorometric method. qPCR was used to quantify and differentiate the fractions of mt-cfDNA and nuclear cfDNA (nc-cfDNA). mt-cfDNA levels in KT patients decreased significantly from baseline to two years post-KT (p < 0.0268), while levels of total cfDNA and nc-cfDNA did not differ. Depending on therapy modality (HD vs. non-HD) before KT, total cfDNA levels were higher in HD patients at both baseline (p = 0.0133) and two years post-KT (p = 0.0421), while nc-cfDNA levels were higher in HD only at baseline (p = 0.0079). Males showed a nonsignificant trend of higher cfDNA levels. Patients with assessed vascular fibrosis (p = 0.0068), either alone or in combination with calcification plus fibrosis, showed reduced mt-cfDNA post-KT (p = 0.0195). Changes in mt-cfDNA levels suggests the impact of KT on the inflammatory state of ESKF, as evidenced via its correlation with high sensitivity C-reactive protein after KT. Further studies are warranted to assess if cfDNA could serve as a noninvasive method for monitoring the response to organ transplantation and even for amelioration of EVA status per se.

Non-invasive rejection surveillance in stable heart transplantation using local laboratory-run donor-derived cell-free DNA assay: two-centre European feasibility study

Abstract Background Monitoring adverse events is crucial after heart transplantation (HTx). Allograft rejection is a major etiological factor of graft dysfunction, hospitalisation, and death posttransplant. Endomyocardial biopsy (EMB) is the standard method of monitoring rejection; however, there are risks and limitations associated with it. The ISHLT guidelines for the care of HTx recipients have included non-invasive surveillance such as testing for donor-derived cell-free DNA (dd-cfDNA). While major studies have been conducted with patient cohorts and centralised testing in the USA, hereby we explored a European two-site cohort where dd-cfDNA was quantified at local centres by next-generation sequencing-based CE-marked assay. Purpose Our objective was to assess feasibility of assay and evaluate dd-cfDNA values in clinically stable HTx recipients. Methods HTx patients were enrolled at their scheduled visits in this cross-sectional study in 2 European HTx centres. Serial data after HTx, including clinical status, maintenance immunosuppression therapy and drug levels, diagnostic tests (blood tests, echocardiograms, coronary angiograms, EMBs), and adverse events were collected. Venous blood specimens were drawn in Streck cfDNA blood collection tubes for quantification of dd-cfDNA levels. We analysed dd-cfDNA fraction in plasma using AlloSeq cfDNA assay. For analysis, clinical stability was defined as asymptomatic patients &amp;gt;28 days post-HTx with normal graft function, without cytomegalovirus infection, history of rejection, or allograft vasculopathy. Results Between July 2021 and December 2022, 50 HTx recipients were enrolled at a median of 274 (112–395) days posttransplant. The median age at enrolment was 55.5 years. Of the total 82 dd-cfDNA results, 34 samples were excluded as they did not meet stability criteria. The median dd-cfDNA value of stable patients was 0.11% (95% CI 0.08%–0.13%). Median levels of dd-cfDNA did not differ between samples drawn in the first year after HTx (n=40) and at later time (n=8) [0.11% vs. 0.11%; p=0.41]. Of the 48 dd-cfDNA samples, 7 had values at risk based on the dd-cfDNA cut-off values from previous clinical validation trials: 4 at the injury cut-off of ≥0.20% and 3 at the severe injury threshold of ≥0.35%. Comparing clinical variables of samples with dd-cfDNA ≥0.20% (n=7) and &amp;lt;0.20% (n=41), we observed a 3-fold, non-significant increase in rate of de novo DSA formation (33.3% vs. 10.8%; p=0.19). Conclusions Our data show feasibility to analyse dd-cfDNA at the local level. In our two-site European reference cohort, dd-cfDNA is present at low levels (median 0.11%) which is within former reported ranges for clinically stable HTx recipients. Levels of dd-cfDNA do not vary beyond the first post-HTx year. The fact that in patients with de novo DSA higher dd-cfDNA levels are found; although, not statistically significant, suggests that dd-cfDNA may be a marker of subclinical rejection and requires further study.

Identification of Renal Transplantation Rejection Biomarkers in Blood Using the Systems Biology Approach.

Renal transplantation plays an essential role in the quality of life of patients with end-stage renal disease. At least 12% of the renal patients receiving transplantations show graft rejection. One of the methods used to diagnose renal transplantation rejection is renal allograft biopsy. This procedure is associated with some risks such as bleeding and arteriovenous fistula formation. In this study, we applied a bioinformatics approach to identify serum markers for graft rejection in patients receiving a renal transplantation. Transcriptomic data were first retrieved from the blood of renal transplantation rejection patients using the GEO database. The data were then used to construct the protein-protein interaction and gene regulatory networks using Cytoscape software. Next, network analysis was performed to identify hub-bottlenecks, and key blood markers involved in renal graft rejection. Lastly, the gene ontology and functional pathways related to hub-bottlenecks were detected using PANTHER and DAVID servers. In PPIN and GRN, SYNCRIP, SQSTM1, GRAMD1A, FAM104A, ND2, TPGS2, ZNF652, RORA, and MALAT1 were the identified critical genes. In GRN, miR-155, miR17, miR146b, miR-200 family, and GATA2 were the factors that regulated critical genes. The MAPK, neurotrophin, and TNF signaling pathways, IL-17, and human cytomegalovirus infection, human papillomavirus infection, and shigellosis were identified as significant pathways involved in graft rejection. The above-mentioned genes can be used as diagnostic and therapeutic serum markers of transplantation rejection in renal patients. The newly predicted biomarkers and pathways require further studies.

Serum CXCL8 Concentration Can Be Used as a Noninvasive Marker of Subclinical Rejection After Pediatric Liver Transplantation.

This study aimed to explore whether serum CXCL8 concentration can be used as a noninvasive marker of subclinical rejection (SCR) after pediatric liver transplantation (pLT). Firstly, RNA sequencing (RNA-seq) was performed on 22 protocol liver biopsy samples. Secondly, several experimental methods were used to verify the RNA-seq results. Finally, the clinical data and serum samples of 520 LT patients in the Department of Pediatric Transplantation of Tianjin First Central Hospital from January 2018 to December 2019 were collected. RNA-seq results indicated that CXCL8 was significantly increased in the SCR group. The results of the 3 experimental methods were consistent with RNA-seq results. According to the 1:2 propensity score matching, 138 patients were divided into the SCR (n = 46) and non-SCR (n = 92) groups. Serological test results indicated that there was no difference in preoperative CXCL8 concentration between the SCR and non-SCR groups ( P > 0.05). However, during protocol biopsy, CXCL8 in the SCR group was significantly higher than in the non-SCR group ( P < 0.001). In diagnosing SCR, receiver operating characteristic curve analysis showed that the area under the curve of CXCL8 was 0.966 (95% confidence interval, 0.938-0.995), sensitivity was 95%, and specificity was 94.6%. In differentiating nonborderline from borderline rejection, the area under the curve of CXCL8 was 0.853 (95% confidence interval, 0.718-0.988), sensitivity was 86.7%, and specificity was 94.6%. This study demonstrates that serum CXCL8 concentration has high accuracy for the diagnosis and disease stratification of SCR after pLT.

Gut microbiota and their metabolite profiles following peripheral nerve xenotransplantation

BackgroundIntestinal pathogens are associated with xenotransplantation tolerance and rejection. However, changes in the gut microbiota in patients who have undergone peripheral nerve xenotransplantation and their association with immune rejection have not yet been reported. ObjectiveWe aimed to explore intestinal microbes and their metabolites at different time points after peripheral nerve transplantation to provide new insight into improving transplant tolerance. MethodsA peripheral nerve xenotransplantation model was constructed by suturing the segmented nerves of Sprague Dawley rats to those of C57 male mice using xenotransplantation nerve bridging. Fecal samples and intestinal contents were collected at three time points: before surgery (Pre group; n = 10), 1 month after transplantation (Pos1 m group; n = 10), and 3 months after transplantation (Pos3 m group; n = 10) for 16S DNA sequencing and nontargeted metabolome detection. ResultsAlpha diversity results suggested that species diversity was significantly downregulated after peripheral nerve xenotransplantation. There were six gut flora genera with significantly different expression levels after xenotransplantation: four were downregulated and two were upregulated. A comparison of the Pre vs. Pos1 m groups and the Pos1 m vs. Pos3 m groups revealed that the most significant differentially expressed Kyoto Encyclopedia of Genes and Genomes metabolite pathways were involved in phenylalanine, tyrosine, and tryptophan biosynthesis, as well as histidine metabolism. Metabolites with a strong relationship to the differentially expressed microbial flora were identified. ConclusionOur study found lower gut microbiome diversity, with increased short-chain fatty acid (SCFA)-producing and sulfate-reducing bacteria at 1 month post peripheral nerve xenotransplantation, and these were decreased at 3 months post-transplantation. The identification of specific bacterial metabolites is essential for recognizing potential diagnostic markers of xenotransplantation rejection or characterizing therapeutic targets to prevent post-transplant infection.

Tissue Expression of Programmed Cell Death 1 Ligand1 (PD-L1) in Biopsies of Transplant Livers of Pediatric Patients as a Possible Marker of Acute Cellular Rejection

Introduction: Preclinical models have demonstrated that PD-1 and its ligand programmed death ligand1 (PD-L1) play significant roles in both graft induction and the maintenance of immune tolerance. It has also been suggested that PD-L1 tissue expression may predict graft rejection; however, the available data are sparse and inconclusive. Some studies were conducted on patients with cancer; most of them do not concern the liver, especially within the context of the use of immunohistochemical tests. Therefore, the aim of our study was to assess the relationship between tissue expression of PD-L1 in a unique material, i.e., in the liver biopsies of pediatric patients after transplantation with the presence of acute cellular rejection (ACR). Material and Methods: This retrospective study enrolled 55 biopsies from 55 patients who underwent protocol liver biopsies. The control group consisted of 19 biopsies from 13 patients diagnosed with acute cellular rejection (rejection activity index/RAI/ from 2 to 8). An immunohistochemical (IHC) staining for PD-L1 was performed in all of the liver specimens; its expression was analyzed in different regions of liver tissue (in inflammatory infiltrates and within the endothelium and hepatocytes). The following changes were re-evaluated in each specimen: features of any kind of rejection (acute cellular, antibody-mediated, chronic); the presence and severity of fibrosis (Ishak scale); and the presence of cholestasis and steatosis. Clinical parameters were also evaluated, including tests of liver function (AST, ALT, GGT, bilirubin). Results: The age of patients in the study group ranged from 2.37 to 18.9 years (median 13.87 years), with the time after transplantation being 1–17 years (median 8.36 years). The age of patients in the control group ranged from 1.48 to 17.51 years (median 7.93 years), with their biopsies being taken 0.62–14.39 years (median 1.33 years) after transplantation. We found a statistically significant relationship between PD-L1 expression on inflammatory infiltrates and ACR; however, there was no statistically significant relationship between PD-L1 endothelial expression and ACR. PD-L1 was not positive in the hepatocytes regardless of if it was the study or control group that was under observation. Conclusion: PD-L1 appears to be a promising marker to predict graft rejection.

Microchimerism as Post-Transplant Marker of a Chronic Rejection Process

The risk of losing a transplanted organ is high, and non-invasive markers to warn of this phenomenon are still being sought. We investigated the impact of post-transplant microchimerism on the function of the transplanted kidney. The study included 100 kidney transplant recipients, mostly women. All transplanted organs were from opposite-sex deceased donors. Microchimerism was assessed using multiplex PCR. Male DNA was detected in all urine samples from female recipients and in 13/56 blood samples from female kidney recipients. Female DNA was found in 31/44 urine samples from male recipients, but in none of the blood samples. Microchimerism in the urine of female recipients correlated positively with blood urea (Rs = 0.45; p = 5.84 × 10−4) and K+ ions (Rs = 0.29; p = 0.03), while microchimerism in the blood of female recipients also correlated positively with blood urea (Rs = 0. 28; p = 0.04), cystatin C (Rs = 0.31; p = 0.02) and the number of incompatible HLA alleles (Rs = 0.42; p = 0.01). A history of DGF was associated with higher urinary donor DNA concentrations in female recipients.: Post-transplant microchimerism may serve as a potential marker of chronic kidney rejection.

#5108 SUSTAINED IL-6 SECRETION CAN LEAD TO AN AMPLIFIED INFLAMMATORY RESPONSE, MEDIATED BY THE ACTIVATION OF STAT3 AND NFKB VIA THE IL-6 AMPLIFIER LOOP

Abstract Background and Aims Organ transplants are the preferred treatment for end-stage organ failure. Potent and specific immunosuppressive agents have significantly decreased acute allograft rejection following renal transplantation. A significant barrier to long-term kidney allograft outcomes is chronic antibody-mediated rejection (CABMR). Chronic inflammation is a major cause of late graft loss that is mediated by soluble mediators released by immune and non-immune cells. IL-6 is a crucial cytokine that plays a central role in developing chronic inflammation. Non-immune cells, such as fibroblasts, have recently been identified as mediating chronic allograft rejection by activating the IL-6 amplifier loop (IL-6+IL-17). Our Aim of the study: -to study the effect of IL-6+IL-17 on secretion of IL-6 in the culture supernatant of fibroblasts derived from renal biopsy of chronic antibody mediated rejection (CABMR) patients; -to see the effect of anti-IL-6 (Tocilizumab)and anti-IL-17 on the secretion of IL-6 from the fibroblasts derived from kidney tissue of chronic antibody mediated rejection (CABMR) patients; and -to elucidate the pro-inflammatory pathway leading to increased IL-6 secretion by induction of Amplifier loop. Method Fibroblasts from grafted kidney from CABMR patients (n = 6) were cultured and stimulated with IL-6 (20ng/ µl), IL-17(50ng/ µl), IL-6 plus IL-17 for 24 hours. Levels of IL-6, MCP-1 and CCL20 were estimated in culture supernatants by ELISA as marker of IL-6 amplifier loop activation. mRNA expression of IL-6, MCP1, CCL20, and SOCS3 genes were measured in the stimulated fibroblasts. Stimulated Renal fibroblast cells from CABMR patients were lysed with Lysis buffer and subjected to SDS–PAGE and western blotting with anti-phospho-STAT3 and anti-phospho-NFκB p65. Additionally, IL-6, MCP1, and CCL20 levels were measured in Healthy control (n = 10), CABMR (n = 20), and non-CABMR (n = 30) patients. Results IL-6 and IL-17 synergistically induced more IL-6, CCL-20 &amp; MCP-1 production from fibroblasts in culture supernatant. Gene expression analysis of IL-6, MCP1, and CCL20 was significantly higher with synergistic activation of IL-6 and IL-17 as compared to either IL-6 or IL-17 alone, while SOCS3 gene expression was downregulated. Our results also suggested that IL-6 Amplifier loop activation induces the NFκB and STAT3 signalling pathway activation in the non-immune cells like fibroblast derived from CABMR patients. Additionally, concentrations of IL-6, CCL-20 &amp; MCP-1 in sera were significantly higher in CABMR patients compared to non-CABMR patients (p&amp;lt;0.001). There was a significant reduction in IL-6 concentration in culture supernatant with IL-6 and IL-17 inhibitor together and mRNA expression of IL-6, CCL20 and MCP-1 was significantly reduced while SOCS3 gene expression was upregulated. Conclusion In humans after kidney transplantation, IL-6 amplifier activation plays an active role in chronic rejection responses. Inhibition of IL-6 with Anti-IL-6 (Tocilizumab) and inhibition of IL-17 with Anti-IL-17 together reduces markers of tissue injury (IL-6, MCP1, CCL20) and rejection of allografts. so, IL-6 amplifier may be a therapeutic target for Chronic transplant rejection.

Is M30 staining a reliable marker predicting graft rejection and fibrosis in protocolar liver biopsies in post-liver transplant pediatric patients?

Liver transplantation is currently a treatment of choice in patients with end-stage liver disease. Acute cellular rejection (ACR), antibody-mediated rejection (AMR), and chronic rejection (ChR) are major causes of graft injury. Therefore, new markers predicting graft rejection are investigating. Apoptosis has been recently proposed as one of the mechanisms contributing to liver fibrosis in liver grafts. Coarse needle liver biopsy is still a gold standard in monitoring post-transplant pathologies. The aim of this study was to assess the utility of immunohistochemical (IHC) staining for M30 (cytokeratin 18), as a prognostic marker of rejection in pediatric recipients of liver transplant and predicting marker of liver fibrosis and worse follow-up. The study enrolled 55 biopsies from 55 patients aged 2.37 to 18.9 years (median 13.87 years) who underwent protocolar liver biopsies taken 1-17 years after liver transplantation (median 8.36 years). The control group (positive control group) consisted of 26 biopsies from 16 patients in whom acute ACR was diagnosed. IHC staining for M30 (cytokeratin 18) and histochemical Azan staining were performed in all liver specimens. The following changes were re-evaluated in each specimen: features of ACR (the severity was assessed using RAI/Rejection Activity Index/Scale, which ranges from 3-9 points and include 3 histopathological changes suggestive of rejection), AMR or ChR; severity of fibrosis (Ishak Scale); presence of cholestasis and steatosis. Clinical parameters including laboratory tests of liver function (AST, ALT, GGTP, bilirubin) were also evaluated. M30 expression correlated with presence of acute cellular rejection. However, no relationship was found between M30 expression and severity of fibrosis. M30 staining, marker of apoptosis, seems to be a promising marker predicting acute cellular rejection.

C4d Staining Is Present in Normal Placentas From Pregnancies Prior to Pregnancy Loss Associated With Chronic Histiocytic Intervillositis and Is Reduced by Immunomodulatory Therapy in Subsequent Pregnancies.

Chronic histiocytic intervillositis (CHI) is associated with adverse pregnancy outcomes and high recurrence risk. Recent studies suggest that CHI may represent a host-vs-graft rejection, and that C4d immunostain can be used as a marker for complement activation and antibody-mediated rejection in the CHI. This retrospective cohort study focused on 5 fetal autopsy cases associated with CHI (5 index cases) from 5 women. We analyzed placentas from the index cases (fetal autopsy cases associated with CHI) and placentas from the women's previous and subsequent pregnancies. We assessed the presence and extent of CHI and C4d immunostaining in these placentas. We evaluated each available placenta and graded the severity of CHI as either <50% or ≥50%. Additionally, we conducted C4d immunostaining on one representative section from each placenta and graded the staining levels as follows: 0+ for staining <5%; 1+ for staining between 5% and <25%; 2+ for staining between 25% and <75%; and 3+ for staining ≥75%. Three of the 5 women had pregnancies prior to their index cases (fetal autopsy cases associated with CHI). Despite the absence of CHI in their initial pregnancies, the placentas displayed positive C4d staining with grades of 1+, 3+, and 3+, respectively. These results suggest the presence of complement activation and antibody-mediated rejection in placentas from their prior pregnancies without CHI. Three of the 5 women received immunomodulatory therapy after experiencing pregnancy losses associated with CHI. After treatment, 2 of these women had live births at 35 and 37 gestational weeks, respectively, while the third had a stillbirth at 25 gestational weeks. The severity of CHI and the degree of C4d staining in the placentas decreased in all 3 cases following immunomodulatory therapies. Specifically, the level of C4d staining decreased from 3+ to 2+, 2+ to 0+, and 3+ to 1+ in these 3 cases, respectively. In women with a history of recurrent pregnancy loss associated with CHI, C4d immunostaining was present in the placentas from their previous non-CHI pregnancies, suggesting activation of the classical complement pathway and antibody-mediated reaction in their prior non-CHI pregnancies before the development of CHI in subsequent pregnancies. Immunomodulatory therapy may improve pregnancy outcomes by reducing complement activation, as shown by the reduction of C4d immunopositivity in the placentas after immunomodulatory treatment. Although we believe that the study provides valuable insights, we acknowledge that there are limitations to the findings. Therefore, to further elucidate the pathogenesis of CHI, additional research efforts with a collaborative and multidisciplinary approach are necessary.