Should IFN-γ, IL-17 and IL-2 be considered predictive biomarkers of acute rejection in liver and kidney transplant? Results of a multicentric study

Plasma immune signatures can predict rejection-free survival in the first year after pediatric liver transplantation

BACKGROUND & AIMS

After pediatric liver transplantation (pLT), children undergo life-long immunosuppression since reliable biomarkers for the assessment of rejection probability are scarce. In the multicentre (n=7) prospective clinical cohort "ChilSFree" study, we aimed to characterize longitudinal dynamics of soluble and cellular immune mediators during the first year after pLT and identify early biomarkers associated with outcome.

METHODS

Using paired Luminex-based multiplex technique and flow cytometry, we characterized longitudinal dynamics of soluble immune mediators (SIM, n=50) and immune cells in the blood of 244 patients at 8 visits over one year: before, 7/14/21/28 days, 3/6/12 months after pLT.

RESULTS

The unsupervised clustering of patients based on SIM profiles revealed 6 unique SIM signatures associated with clinical outcome. From 3 signatures linked to improved outcome, one was associated with one-year-long rejection-free survival and stable graft function and was characterized by low levels of pro-inflammatory (CXCL8/9/10/12, CCL7, SCGF-β, sICAM-1), high levels of regenerative (SCF, TNF-β), and pro-apoptotic (TRAIL) SIM (all, p<0.001, fold change >100). Of note, this SIM signature appeared two weeks after pLT and remained stable over the entire year, pointing towards its potential as a novel early biomarker for minimizing or weaning immunosuppression. In the blood of these patients, a higher frequency of CD56bright NK cells (p<0.01), a known hallmark also associated with operationally tolerant pLT patients, was detected. The concordance of the model for prediction of rejection based on identified SIM signatures was 0.715, and 0.795, in combination with living-related transplantation as co-variate, respectively.

CONCLUSIONS

SIM blood signatures may enable the non-invasive and early assessment of rejection risks in the first year after pLT, paving the way to improved therapeutic options.

Dynamic immune recovery process after liver transplantation revealed by single-cell multi-omics analysis

Elucidating the temporal process of immune remodeling under immunosuppressive treatment after liver transplantation (LT) is critical for precise clinical management strategies. Here, we performed a single-cell multi-omics analysis of peripheral blood mononuclear cells (PBMCs) collected from LT patients (with and without acute cellular rejection [ACR]) at 13 time points. Validation was performed in two independent cohorts with additional LT patients and healthy controls. Our study revealed a four-phase recovery process after LT and delineated changes in immune cell composition, expression programs, and interactions along this process. The intensity of the immune response differs between the ACR and non-ACR patients. Notably, the newly identified inflamed NK cells, CD14+RNASE2+ monocytes, and FOS-expressing monocytes emerged as predictive indicators of ACR. This study illuminates the longitudinal evolution of the immune cell landscape under tacrolimus-based immunosuppressive treatment during LT recovery, providing a four-phase framework that aids the clinical management of LT patients.

Single-cell and bulk RNA sequencing highlights the role of M1-like infiltrating macrophages in antibody-mediated rejection after kidney transplantation

Background

Antibody-mediated rejection (ABMR) significantly affects transplanted kidney survival, yet the macrophage phenotype, ontogeny, and mechanisms in ABMR remain unclear.

Method

We analyzed post-transplant sequencing and clinical data from GEO and ArrayExpress. Using dimensionality reduction and clustering on scRNA-seq data, we identified macrophage subpopulations and compared their infiltration in ABMR and non-rejection cases. Cibersort quantified these subpopulations in bulk samples. Cellchat, SCENIC, monocle2, and monocle3 helped explore intercellular interactions, predict transcription factors, and simulate differentiation of cell subsets. The Scissor method linked macrophage subgroups with transplant prognosis. Furthermore, hdWGCNA, nichnet, and lasso regression identified key genes associated with core transcription factors in selected macrophages, validated by external datasets.

Results

Six macrophage subgroups were identified in five post-transplant kidney biopsies. M1-like infiltrating macrophages, prevalent in ABMR, correlated with pathological injury severity. MIF acted as a primary intercellular signal in these macrophages. STAT1 regulated monocyte-to-M1-like phenotype transformation, impacting transplant prognosis via the IFNγ pathway. The prognostic models built on the upstream and downstream genes of STAT1 effectively predicted transplant survival. The TLR4-STAT1-PARP9 axis may regulate the pro-inflammatory phenotype of M1-like infiltrating macrophages, identifying PARP9 as a potential target for mitigating ABMR inflammation.

Conclusion

Our study delineates the macrophage landscape in ABMR post-kidney transplantation, underscoring the detrimental impact of M1-like infiltrating macrophages on ABMR pathology and prognosis.

Transplantation: platform to study recurrence of disease

Beyond the direct benefit that a transplanted organ provides to an individual recipient, the study of the transplant process has the potential to create a better understanding of the pathogenesis, etiology, progression and possible therapy for recurrence of disease after transplantation while at the same time providing insight into the original disease. Specific examples of this include: 1) recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation, 2) recurrent autoimmunity after pancreas transplantation, and 3) recurrence of disease after orthotopic liver transplantation (OLT) for cirrhosis related to progressive steatosis secondary to jejuno-ileal bypass (JIB) surgery. Our team has been studying these phenomena and their immunologic underpinnings, and we suggest that expanding the concept to other pathologic processes and/or transplanted organs that harbor the risk for recurrent disease may provide novel insight into the pathogenesis of a host of other disease processes that lead to organ failure.

Immature and activated phenotype of blood NK cells is associated with acute rejection in adult liver transplant

Natural killer (NK) cells contribute to liver transplant (LTx) rejection. However, the blood-circulating NK-cell dynamics of patients who experience acute rejection (AR) are unclear. Herein, we longitudinally profiled the total NK cells and their subsets, along with the expression of activating and inhibitory receptors in sequential peripheral blood mononuclear cell samples, spanning from before LTx to the first year after LTx of 32 patients with AR and 30 patients under a steady immune status. Before transplantation, patients with AR (rejectors) contained a significantly higher proportion of the immature CD56 bright CD16 - subset and a lower cytolytic CD56 dim CD16 + in the total blood-circulating NK cells than patients with steady immunity. Both subsets contained a high NKp30-positive population, and CD56 dim CD16 + additionally exhibited a high NKp46-positive ratio. The NKp30-positive ratio in CD56 dim CD16 + subset showed the most prominent AR predictive ability before LTx and was an independent risk factor of LTx AR. After transplantation, the blood-circulating NK cells in rejectors maintained a higher CD56 bright CD16 - and lower CD56 dim CD16 + composition than the controls throughout the first year after LTx. Moreover, both subsets maintained a high NKp30-positive ratio, and CD56 dim CD16 + retained a high NKp46-positive ratio. The blood-circulating NK cell subset composition was consistent during AR, while the expressions of NKp30 and NKp46 were augmented. Collectively, a more immature CD56 bright CD16 - subset composition and an activated phenotype of high NKp30 expression were the general properties of blood-circulating NK cells in rejected LTx recipients, and the NKp30-positive ratio in CD56 dim CD16 + NK subset before LTx possessed AR predictive potential.

Immune surveillance and humoral immune responses in kidney transplantation - A look back at T follicular helper cells

T follicular helper cells comprise a specialized, heterogeneous subset of immune-competent T helper cells capable of influencing B cell responses in lymphoid tissues. In physiology, for example in response to microbial challenges or vaccination, this interaction chiefly results in the production of protecting antibodies and humoral memory. In the context of kidney transplantation, however, immune surveillance provided by T follicular helper cells can take a life of its own despite matching of human leukocyte antigens and employing the latest immunosuppressive regiments. This puts kidney transplant recipients at risk of subclinical and clinical rejection episodes with a potential risk for allograft loss. In this review, the current understanding of immune surveillance provided by T follicular helper cells is briefly described in physiological responses to contrast those pathological responses observed after kidney transplantation. Sensitization of T follicular helper cells with the subsequent emergence of detectable donor-specific human leukocyte antigen antibodies, non-human leukocyte antigen antibodies their implication for kidney transplantation and lessons learnt from other transplantation "settings" with special attention to antibody-mediated rejection will be addressed.

Monitoring of Serological, Cellular and Genomic Biomarkers in Transplantation, Computational Prediction Models and Role of Cell-Free DNA in Transplant Outcome

The process and evolution of an organ transplant procedure has evolved in terms of the prevention of immunological rejection with the improvement in the determination of immune response genes. These techniques include considering more important genes, more polymorphism detection, more refinement of the response motifs, as well as the analysis of epitopes and eplets, its capacity to fix complement, the PIRCHE algorithm and post-transplant monitoring with promising new biomarkers that surpass the classic serum markers such as creatine and other similar parameters of renal function. Among these new biomarkers, we analyze new serological, urine, cellular, genomic and transcriptomic biomarkers and computational prediction, with particular attention to the analysis of donor free circulating DNA as an optimal marker of kidney damage.

Importance of human leukocyte antigen antibodies and leukocyte antigen/killer-cell immunoglobulin-like receptor genes in liver transplantation

Many mechanisms have been proposed to explain the hypothetical state of hepatic tolerance, which is described by eventual imbalances or deregulation in the balance of cytokines, mediators, effectors, and regulatory cells in the complex milieu of the liver. In this section, we will comment on the importance of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) as well as the compatibility and pairings of HLA and killer-cell immunoglobulin-like receptor (KIR) genotypes in the evolution of liver transplantation. Thus, HLA compatibility, viral infections, and HLA-C/KIR combinations have all been linked to liver transplant rejection and survival. There have been reports of increased risk of acute and chronic rejection with ductopenia, faster graft fibrosis, biliary problems, poorer survival, and even de novo autoimmune hepatitis when DSAs are present in the recipient. Higher mean fluorescence intensity (MFI) values of the DSAs and smaller graft size were associated with poorer patient outcomes, implying that high-risk patients with preformed DSAs should be considered for selecting the graft placed and desensitization methods, according to the investigators. Similarly, in a combined kidney-liver transplant, a pretransplant with a visible expression of several DSAs revealed that these antibodies were resistant to treatment. The renal graft was lost owing to antibody-mediated rejection (AMR). The HLA antigens expressed by the transplanted liver graft influenced antibody elimination. Pathologists are increasingly diagnosing AMR in liver transplants, and desensitization therapy has even been employed in situations of AMR, particularly in patients with DSAs in kidney-hepatic transplants and high-class II MFI due to Luminex. In conclusion, after revealing the negative impacts of DSAs with high MFI, pretransplant virtual crossmatch techniques may be appropriate to improve evolution; however, they may extend cold ischemia periods by requiring the donor to be typed.

Diagnosing Acute Cellular Rejection after Paediatric Liver Transplantation-Is There Room for Interleukin Profiles?

BACKGROUND

The current gold standard to diagnose T-cell-mediated acute rejection (TCMR) requires liver histology. Using data from the ChilSFree study on immune response after paediatric liver transplantation (pLT), we aimed to assess whether soluble cytokines can serve as an alternative diagnostic tool in children suspected to have TCMR.

METHODS

A total of n = 53 blood samples obtained on the day of or up to 3 days before liver biopsy performed for suspected TCMR at median 18 days (range 7-427) after pLT in n = 50 children (38% female, age at pLT 1.8 (0.5-17.5) years) were analysed for circulating cytokine levels using Luminex-based Multiplex technology. Diagnostic accuracy of cytokine concentrations was assessed using a multivariable model based on elastic net regression and gradient boosting machine analysis.

RESULTS

TCMR was present in 68% of biopsies. There was strong evidence that patients with TCMR had increased levels of soluble CXCL8, CXCL9, CXCL10, IL-16, IL-18, HGF, CCL4, MIF, SCGF-β, and HGF before biopsy. There was some evidence for increased levels of sCD25, ICAM-1, IL-6, IL-3, and CCL11. Diagnostic value of both single cytokine levels and a combination of cytokines and clinical markers was poor, with AUROCs not exceeding 0.7.

CONCLUSION

Patients with TCMR showed raised levels of cytokines and chemokines reflective of T-cell activation and chemotaxis. Despite giving insight into the mechanisms of TCMR, the diagnostic value of soluble cytokines for the confirmation of TCMR in a clinical scenario of suspected TCMR is poor.

Human embryonic stem cell-derived melanocytes exhibit limited immunogenicity

Although surgical interventions have become optional for refractory vitiligo, grafting related injuries is inevitable. Embryonic stem cell (ESC) derivatives can be used in transplantation to address this issue, but the immune rejection due to allogeneic transplantation is of great concern. To investigate the immunogenicity of ESC derived melanocytes (ES-MC), we established a co-culture system of ES-MC and allogeneic PBMC. The results showed that ES-MC were similar to human primary melanocytes, with low expression of immune related molecules, and limited capability of stimulating allogeneic lymphocytes in vitro. Taken together, our findings confirm that ES-MC are of limited immunogenicity, providing new insights into the application of ES-MC in the regenerative medicine such as treating vitiligo.

Getting immunosuppression just right: the role of clinical biomarkers in predicting patient response post solid organ transplantation

INTRODUCTION

Actually, immunosuppression selection isn't based on individual immune alloreactivity, and immunosuppressive drug dosing is mainly based on the development of toxicity and the achievement of specific target concentrations. Since a successful outcome requires optimal patient risk stratification and treatment, several groups have evaluated candidate biomarkers that have shown promise in the assessment of individual immune responses, the prediction of personal pharmacodynamic effects of immunosuppressive drugs and the prognosis and diagnosis of graft outcomes..

AREAS COVERED

This review includes biomarkers that the Scientific Community in Solid Organ Transplantation currently considers to have potential as diagnostic and prognostic biomarkers of graft evolution. We have focused on recent scientific advances and expert recommendations regarding the role of specific and non-specific pharmacodynamic biomarkers that are mainly involved in the T-cell-mediated response.

EXPERT OPINION

Integral pharmacologic monitoring that combines pharmacokinetics, pharmacogenetics and predictive pharmacodynamic biomarkers may provide crucial information and allow personal adjustment of immunosuppressive drugs at an early stage before severe adverse events ensue. Multicentre, randomized, prospective and interventional trials are needed to fine tune the established cut-off values for each biomarker and the optimal monitoring frequency for each biomarker and to accurately evaluate possible clinical confounding factors to enable correct clinical qualification.

Cytokines in Liver Transplantation

Cytokines, soluble mediators of the immune system, play a critical role in the pathogenesis of autoimmune, allergic and infectious diseases. They are also implicated in the initiation and development of allograft rejection. During recent years, there have been considerable advances in generating novel anti-cytokine agents with promoted efficacy and safety, which could be administrated for managing dysregulated cytokine secretion; besides, gene therapy for overexpression of immunomodulatory cytokines has shown substantial improvements. Liver transplantation has been established as a life-saving treatment for end-stage hepatic diseases but the growing number of recipients urge for improved post-transplant care including tolerance induction, infection control and resolving immunosuppressant drugs adverse effects. Cytokines with a wide range of proinflammatory and regulatory properties might be considered as potential therapeutic targets for selective suppression or enhancement of the immune responses in recipients. In the present review, we aimed to summarize the positive and negative effects of cytokines on liver allograft in addition to their prognostic and therapeutic values.

Aspirin Attenuates Cardiac Allograft Rejection by Inhibiting the Maturation of Dendritic Cells via the NF-κB Signaling Pathway

Background: Dendritic cells (DCs) serve as an important part of the immune system and play a dual role in immune response. Mature DCs can initiate immune response, while immature or semi-mature DCs induce immune hyporesponsiveness or tolerance. Previous studies have shown that aspirin can effectively inhibit the maturation of DCs. However, the protective effect of aspirin on acute cardiac allograft rejection has not been studied. The aim of this study was to elucidate the effect of aspirin exert on allograft rejection. Methods: The model of MHC-mismatched (BALB/c to B6 mice) heterotopic heart transplantation was established and administered intraperitoneal injection with aspirin. The severity of allograft rejection, transcriptional levels of cytokines, and characteristics of immune cells were assessed. Bone marrow-derived dendritic cells (BMDCs) were generated with or without aspirin. The function of DCs was determined via mixed lymphocyte reaction (MLR). The signaling pathway of DCs was detected by Western blotting. Results: Aspirin significantly prolonged the survival of cardiac allograft in mouse, inhibited the production of pro-inflammatory cytokines and the differentiation of effector T cells (Th1 and Th17), as well as promoted the regulatory T cells (Treg). The maturation of DCs in the spleen was obviously suppressed with aspirin treatment. In vitro, aspirin decreased the activation of NF-κB signaling of DCs, as well as impeded MHCII and co-stimulatory molecules (CD80, CD86, and CD40) expression on DCs. Moreover, both the pro-inflammatory cytokines and function of DCs were suppressed by aspirin. Conclusion: Aspirin inhibits the maturation of DCs through the NF-κB signaling pathway and attenuates acute cardiac allograft rejection.

Protective Role of Kynurenine 3-Monooxygenase in Allograft Rejection and Tubular Injury in Kidney Transplantation

Renal tubular epithelial cells (TECs) are the primary targets of ischemia-reperfusion injury (IRI) and rejection by the recipient's immune response in kidney transplantation (KTx). However, the molecular mechanism of rejection and IRI remains to be identified. Our previous study demonstrated that kynurenine 3-monooxygenase (KMO) and kynureninase were reduced in ischemia-reperfusion procedure and further decreased in rejection allografts among mismatched pig KTx. Herein, we reveal that TEC injury in acutely rejection allografts is associated with alterations of Bcl2 family proteins, reduction of tight junction protein 1 (TJP1), and TEC-specific KMO. Three cytokines, IFN γ , TNFα, and IL1β, reported in our previous investigation were identified as triggers of TEC injury by altering the expression of Bcl2, BID, and TJP1. Allograft rejection and TEC injury were always associated with a dramatic reduction of KMO. 3HK and 3HAA, as direct and downstream products of KMO, effectively protected TEC from injury via increasing expression of Bcl-xL and TJP1. Both 3HK and 3HAA further prevented allograft rejection by inhibiting T cell proliferation and up-regulating aryl hydrocarbon receptor expression. Pig KTx with the administration of DNA nanoparticles (DNP) that induce expression of indoleamine 2,3-dioxygenase (IDO) and KMO to increase 3HK/3HAA showed an improvement of allograft rejection as well as murine skin transplant in IDO knockout mice with the injection of 3HK indicated a dramatic reduction of allograft rejection. Taken together, our data provide strong evidence that reduction of KMO in the graft is a key mediator of allograft rejection and loss. KMO can effectively improve allograft outcome by attenuating allograft rejection and maintaining graft barrier function.

Consideration of IL-2, IFN-γ and IL-4 expression and methylation levels in CD4+ T cells as a predictor of rejection in kidney transplant

Kidney transplantation is the certain treatment for the end-stage-kidney disease patients. However after transplantation, allograft rejection or graft dysfunction are serious problems which the patients can be encountered. In several studies new biomarkers to predict rejection episodes tried to be evaluated and cytokines are thought to be one of these biomarkers. Additionally, epigenetic regulation of the cytokine genes can be an opportunity to detect the graft survival or dysfunction that lead to rejection. In this study, we aimed to detect the expression levels and methylation profile of cytokines IL-2, IL-4 and IFN-γ to follow the clinical situation of the patients. 25 kidney transplant patients were included in our study group and peripheral blood samples were collected before and 6 months after transplantation. CD4+ T cells were separated by using magnetic separation system and expression levels are detected by qPCR while methylation profile analysis was performed by pyrosequencing. According to our study we noticed that all of the patients with allograft rejection have increased expression levels of IFN-γ. When methylation profile of the CpGs in the promotor region of IFN-γ is evaluated, +128CpG was found as methylated when compared with +122. In conclusion, epigenetic mechanisms can effect several processed in renal transplantation and further studies with higher numbers of patients are needed to detect new biomarkers for prediction of allograft rejection.

A high concentration of TGF-β correlates with opportunistic infection in liver and kidney transplantation

Transforming growth factor-β (TGF-β) has been associated with numerous human infections, but its role in the occurrence of opportunistic infection (OI) after solid organ transplantation remains unexplored. This study aimed to assess the utility of the TGF-β following in vitro stimulation of whole peripheral blood (WPB) as a surrogate biomarker of post-transplant OI in a cohort of liver and kidney recipients. Thirty liver and thirty-one kidney transplant recipients were recruited to be prospectively monitored for one-year post-transplantation. Enzyme-linked immunosorbent assay (ELISA) was performed to calculate IFN-γ, IL-17, IL-10 and TGF-β concentration in the supernatant from the activated WPB. Recipients showed higher TGF-β concentrations compared to IFN-γ, IL-17, IL-10 at baseline, although these differences were not significant between INF and NoINF. However, recipients who developed an OI within the first sixth months had a higher concentration of TGF-β than those without OI. A concentration of TGF-β > 363.25 pg/ml in liver and TGF-β > 808.51 pg/ml in kidney recipients were able to stratify patients at high risk of OI with a sensitivity and specificity above 70% in both types of solid organ transplantations. TGF-β could provide valuable information for the management of liver and kidney recipients at risk of post-transplant infection.

T helper 17 cells in the pathophysiology of acute and chronic kidney disease

Both acute and chronic kidney disease have a strong underlying inflammatory component. This review focuses primarily on T helper 17 (Th17) cells as mediators of inflammation and their potential to modulate acute and chronic kidney disease. We provide updated information on factors and signaling pathways that promote Th17 cell differentiation with specific reference to kidney disease. We highlight numerous clinical studies that have investigated Th17 cells in the setting of human kidney disease and provide updated summaries from various experimental animal models of kidney disease indicating an important role for Th17 cells in renal fibrosis and hypertension. We focus on the pleiotropic effects of Th17 cells in different renal cell types as potentially relevant to the pathogenesis of kidney disease. Finally, we highlight studies that present contrasting roles for Th17 cells in kidney disease progression.

Recurrence of Hepatocellular Carcinoma After Liver Transplantation is Associated with Episodes of Acute Rejections

Purpose

The impact of acute rejection (AR) after liver transplantation (LT) for hepatocellular carcinoma (HCC) on patient outcome is uncertain. This aim of this study is to investigate whether AR is associated with HCC relapse and overall survival.

Patients and Methods

Patients undergoing LT for HCC between 2001 and 2015 were retrospectively analyzed with regard to histopathological proven AR within the median time until recurrence. Cox’s regression analysis was conducted revealing risk factors for HCC recurrence.

Results

HCC recurred in 47 of 252 analyzed patients with a median time to recurrence of 20 months. Patients with AR (28.6%) had a significantly higher frequency of recurrence compared to patients without AR (13.0%, p=0.002). Multiple Cox regression analyses identified AR within 20 months to be an independent risk factor for HCC recurrence both as dichotomized (HR=2.91, 95%CI: 1.30–6.53; p=0.009) and as a continuous variable (HR=1.81, 95%CI: 1.28–2.54; p=0.001). HCC recurrence and AR were associated with higher grades of liver fibrosis one year after LT, when compared to patients without AR (p=0.019).

Conclusion

Our results demonstrate an association of AR with HCC recurrence after LT with implications for intervals of monitoring in tumor surveillance. Graft fibrosis and immune mechanisms are potentially related and causal interactions are worth further investigation.

PCR Array Technology in Biopsy Samples Identifies Up-Regulated mTOR Pathway Genes as Potential Rejection Biomarkers After Kidney Transplantation

Background: Antibody-mediated rejection (AMR) is the major cause of kidney transplant rejection. The donor-specific human leukocyte antigen (HLA) antibody (DSA) response to a renal allograft is not fully understood yet. mTOR complex has been described in the accommodation or rejection of transplants and integrates responses from a wide variety of signals. The aim of this study was to analyze the expression of the mTOR pathway genes in a large cohort of kidney transplant patients to determine its possible influence on the transplant outcome. Methods: A total of 269 kidney transplant patients monitored for DSA were studied. The patients were divided into two groups, one with recipients that had transplant rejection (+DSA/+AMR) and a second group of recipients without rejection (+DSA/-AMR and -DSA/-AMR, controls). Total RNA was extracted from kidney biopsies and reverse transcribed to cDNA. Human mTOR-PCR array technology was used to determine the expression of 84 mTOR pathway genes. STRING and REVIGO software were used to simulate gene to gene interaction and to assign a molecular function. Results: The studied groups showed a different expression of the mTOR pathway related genes. Recipients that had transplant rejection showed an over-expressed transcript (≥5-fold) of AKT1S1, DDIT4, EIF4E, HRAS, IGF1, INS, IRS1, PIK3CD, PIK3CG, PRKAG3, PRKCB (>12-fold), PRKCG, RPS6KA2, TELO2, ULK1, and VEGFC, compared with patients that did not have rejection. AKT1S1 transcripts were more expressed in +DSA/-AMR biopsies compared with +DSA/+AMR. The main molecular functions of up-regulated gene products were phosphotransferase activity, insulin-like grown factor receptor and ribonucleoside phosphate binding. The group of patients with transplant rejection also showed an under-expressed transcript (≥5-fold) of VEGFA (>15-fold), RPS6, and RHOA compared with the group without rejection. The molecular function of down-regulated gene products such as protein kinase activity and carbohydrate derivative binding proteins was also analyzed. Conclusions: We have found a higher number of over-expressed mTOR pathway genes than under-expressed ones in biopsies from rejected kidney transplants (+DSA/+AMR) with respect to controls. In addition to this, the molecular function of both types of transcripts (over/under expressed) is different. Therefore, further studies are needed to determine if variations in gene expression profiles can act as predictors of graft loss, and a better understanding of the mechanisms of action of the involved proteins would be necessary.

Assessment of the Effect of Baicalin on Duck Virus Hepatitis

BACKGROUND

Duck virus hepatitis (DVH) caused by duck hepatitis A virus type 1 (DHAV-1) is a malignant disease in ducklings, causing economic losses in the duck industry. However, there is still no antiviral drug against DHAV-1 in the clinic.

OBJECTIVE

Our aim is to investigate the anti-DHAV-1 effect of baicalin, which is a flavonoid derived from the Chinese medicinal herb huangqin (Scutellaria baicalensis Georgi).

METHODS

Here, we first detected its anti-DHAV-1 ability in vitro and in vivo. At the same time, the inhibition of baicalin on DHAV-1 reproduction was determined. Finally, we tested and verified the anti-oxidative and immuno-enhancing roles of baicalin on its curative effect on DVH.

RESULTS

Baicalin possessed anti-DHAV-1 effect. It improved the cytoactive of DEH which was infected by DHAV-1 as well as reduced the DHAV-1 reproduction in DEH. Under baicalin treatment, mortality of ducklings infected by DHAV-1 decreased, additionally the DHAV-1 level and liver injury in such ducklings were significantly reduced or alleviated. The in vitro mechanism study indicated baicalin inhibited DHAV-1 reproduction via interfering the viral replication and release. Furthermore, the in vivo mechanism study manifested both the anti-oxidative and immuno-enhancing abilities of baicalin, which played crucial roles in its curative effect on DVH.

CONCLUSION

This study may provide a scientific basis for developing baicalin as one or a part of the anti-DHAV-1 drugs.

Maintenance Immunosuppression in Solid Organ Transplantation: Integrating Novel Pharmacodynamic Biomarkers to Inform Calcineurin Inhibitor Dose Selection

Calcineurin inhibitors, the primary immunosuppressive therapy used to prevent alloreactivity of transplanted organs, have a narrow therapeutic index. Currently, treatment is individualized based on clinical assessment of the risk of rejection or toxicity guided by trough concentration monitoring. Advances in immune monitoring have identified potential markers that may have value in understanding calcineurin inhibitor pharmacodynamics. Integration of these markers has the potential to complement therapeutic drug monitoring. Existing pharmacokinetic-pharmacodynamic (PK-PD) data is largely limited to correlation between the biomarker and trough concentrations at single time points. Immune related gene expression currently has the most evidence supporting PK-PD integration. Novel biomarker-based approaches to pharmacodynamic monitoring including development of enhanced PK-PD models are proposed to realize the full clinical benefit.

[Summary of the recommendations of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT) on the therapeutic drug monitoring of tacrolimus]

Recently, the International Association of Therapeutic Drug Monitoring (IATDMCT), that is the learning society for biological pharmacology and toxicology, issued recommendations on the therapeutic drug monitoring (TDM) of tacrolimus. This is the second consensus after the one issued in 2009. In this document, the role of tacrolimus TDM for the four principal transplanted organs is discussed. The analytical aspects, pharmacogenetics, TDM alternative approaches and the positioning of biomarkers are also presented. Stronger recommendations are about trough concentration targets in kidney and liver transplantation and for other indication of tacrolimus use. For the first time, an area under the curve of tacrolimus concentrations target is recommended for recipients management. Eventually, another set of recommendations are proposed for pharmacodynamic biomarkers used in patients' follow-up.

Nuclear factor of activated T cells as potential pharmacodynamic biomarker for the risk of acute and subclinical rejection in de novo liver recipients

BACKGROUND & AIMS

Nuclear factor of activated T cell-regulated gene expression (NFAT-RGE) has been proposed as a pharmacodynamic biomarker for tacrolimus (Tac) and cyclosporine (CsA). Our aim was to evaluate the role of NFAT-RGE in modulating intralymphocytary IL-2 and IFN-γ expression and its clinical utility as an early non-invasive predictive biomarker for the risk of acute rejection (AR) and infection in de novo liver transplant (LT) recipients.

METHODS

Fifty-six LT recipients treated with Tac or CsA [with and without mycophenolate mofetil (MMF)] were included: 30 free of rejection or infection, 11 rejectors (T cell-mediated acute rejection), 5 with subclinical rejection (SCR) and 10 with cytomegalovirus (CMV) infection. Within the first 3 months after transplantation, NFAT-RGE of IL-2, IFN-γ and GM-CSF and intralymphocytary synthesis of IL-2 and IFN-γ were evaluated by real-time PCR and flow cytometry respectively.

RESULTS

A significant increase in NFAT-RGE was observed in patients who experienced TCMAR (75% [42-100%]) or SCR (41% [18-78%]) compared with patients without rejection or infection (14% [2-23%]). Positive correlations between the %NFAT-RGE-IFN and both the %CD8CD69IFN-γ and %CD4CD69IFN-γ and between the %NFAT-RGE-IL2 and the %CD8CD69IL2 were observed. NFAT-RGE was significantly lower in CMV⁺ patients than in non-infected patients. Finally, an inverse correlation between the Tac or CsA concentration and inhibition of NFAT-RGE were observed.

CONCLUSIONS

Sequential post-transplantation NFAT-RGE monitoring combined with intralymphocytary IL-2 and IFN-γ before transplantation and at the first and third month post-transplantation may be key predictive and diagnostic biomarkers for the risk of TCMAR and SCR and better guide CNi therapy in LT patients.

Cytokine Profiles in Children After Pediatric Kidney Transplantation With Acute Cellular Compared to Chronic Antibody-mediated Rejection and Stable Patients: A Pilot Study

Different patterns of plasma cytokines can be expected in the case of chronic active-antibody-mediated (cAMR) and acute cellular rejection (AR) after kidney transplantation (KTx).

Monitoring of miR-181a-5p and miR-155-5p Plasmatic Expression as Prognostic Biomarkers for Acute and Subclinical Rejection in de novo Adult Liver Transplant Recipients

Background and Aims: News strategies for the accurate assessment of the state of immunosuppression (IS) in liver transplant recipients are needed to prevent rejection and minimize drug-related side effects. miRNAs can potentially be used as diagnostic or prognostic biomarkers in transplant patients. This study evaluated the capacity of a plasmatic miRNA panel (miR-155-5p, miR-122-5p, miR-181a-5p, and miR148-3p) as an early non-invasive prognostic and diagnostic biomarker for T cell-mediated acute rejection (TCMAR) and subclinical rejection (SCR) in adult liver recipients. Methods: A total of 145 liver recipients were included. All patients received a calcineurin inhibitor with or without mycophenolate mofetil and methylprednisolone. Plasmatic miRNA expression was assessed by qPCR before and at different time-points after liver transplantation. Results: Seventeen patients experienced TCMAR, and eight were diagnosed with SCR during the protocol biopsy at the 3rd month post-transplantation. Pre-transplantation, miR-155-5p expression was significantly higher in TCMAR patients and in SCR patients than in non-rejectors, and miR-181a-5p expression was also significantly higher in SCR patients than in non-rejectors. Post-transplantation, before transaminase-level modification, significantly increased miR-181a-5p, miR-155-5p, and miR-122-5p expression was observed in TCMAR and SCR patients. Binary logistic regression analyses showed, post-transplantation, that TCMAR risk was better predicted by individual expression of miR-181a-5p (LOGIT = -6.35 + 3.87*miR-181a-5p), and SCR risk was better predicted by the combination of miR-181a-5p and miR-155-5p expression (LOGIT = -5.18 + 2.27*miR-181a-5p+1.74*miR-155-5p). Conclusions: Pre-transplantation plasmatic miR-155-5p expression may be useful for stratifying low-immunologic-risk patients, and post-transplantation miR-181a-5p and miR-155-5p may be candidates for inclusion in early, non-invasive prognostic biomarker panels to prevent TCMAR or SCR and better identify patient candidates for IS minimization. Large prospective randomized multicenter trials are needed to refine the cut-off values and algorithms and validate the clinical usefulness of these biomarkers.

IL17A and IL17F genes polymorphisms are associated with histopathological changes in transplanted kidney

Background

Interleukin 17 is a proinflammatory cytokine involved in immune response after allograft transplantation. IL-17 family of proinflammatory cytokines includes IL-17A and IL-17F. Previous studies have demonstrated that the rs2275913 IL17A and the rs11465553 IL17F gene polymorphism are associated with kidney allograft function. Because of the association between these polymorphisms and post-transplant immune response, we assume that these single nucleotide polymorphisms may affect morphological structure of transplanted kidney.

The aim of this study was to examine the association of rs2275913 IL17A and rs2397084, rs11465553 and rs763780 IL17F gene polymorphisms with histopathological changes in transplanted kidney biopsies such as: glomerulitis, tubulitis, arteritis, cell infilitration and fibrosis.

Methods

The study enrolled 82 patients after renal graft transplantation in whom a kidney biopsy was performed because of impaired graft function. The rs2397084 T > C (Glu126Gly), rs11465553 G > A (Val155Ile) and rs763780 T > C (His167Arg) polymorphisms within the IL17F gene and the rs2275913 A > G (− 197 A > G) polymorphism within the IL17A gene promoter were genotyped using TaqMan genotyping assays on a 7500 FAST Real-Time PCR System (Applied Biosystems, USA).

Results

There was a significant association between the rs2275913 IL17A gene polymorphism and the grade of tubulitis, which was more severe among patients with the A allele, compared to recipients with the GG genotype (GG vs. AG + AA, P = 0.02), and with the grade of arteriolar hyaline thickening and mesangial matrix increase, which were more severe among patients with the G allele compared to recipients with the AA genotype (AA vs. AG + GG, P = 0.01 and P = 0.04, respectively). Tubular atrophy and interstitial fibrosis were more severe among individuals with the C allele at the rs763780 IL17F gene polymorphism (TT vs. TC, P = 0.09 and P = 0.017, respectively). However, it should be taken into account that the statistical significance was achieved without correction for multiple testing, and no significant association would remain significant after such correction.

Conclusions

The results of this study may suggest a possible association between the rs2275913 IL17A and rs2275913 IL17A gene polymorphisms and some histopathological changes in transplanted kidney biopsies.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1308-z) contains supplementary material, which is available to authorized users.

IL-17A - A regulator in acute inflammation: Insights from in vitro, in vivo and in silico studies

Acute inflammation following sterile injury is both inevitable and necessary to restore homeostasis and promote tissue repair. However, when excessive, inflammation can jeopardize the viability of organs and cause detrimental systemic effects. Identifying key-regulators of the immune cascade induced by surgery is vital to attenuating excessive inflammation and its subsequent effects. In this review, we describe the emerging role of IL-17A as a key-regulator in acute inflammation. The role of IL-17A in chronic disease states, such as rheumatoid arthritis, psoriasis and cancer has been well documented, but its significance in acute inflammation following surgery, sepsis, or traumatic injury has not been well studied. We aim to highlight the role of IL-17A in acute inflammation caused by trauma, liver ischemia, and organ transplantation, as well as in post-operative surgical infections. Further investigation of the roles of this cytokine in acute inflammation may stimulate novel therapies or diagnostic modalities.

Immune monitoring after pediatric liver transplantation - the prospective ChilSFree cohort study

Background

Although trough levels of immunosuppressive drugs are largely used to monitor immunosuppressive therapy after solid organ transplantation, there is still no established tool that allows for a validated assessment of functional degree of immunosuppression or the identification of clinically relevant over- or under-immunosuppression, depending on graft homeostasis. Reliable non-invasive markers to predict biopsy proven acute rejection (BPAR) do not exist. Literature data suggest that longitudinal measurements of immune markers might be predictive of BPAR, but data in children are scarce. We therefore propose an observational prospective cohort study focusing on immune monitoring in children after liver transplantation. We aim to describe immune function in a cohort of children before and during the first year after liver transplantation and plan to investigate how the immune function profile is associated with clinical and laboratory findings.

Methods

In an international multicenter prospective approach, children with end-stage liver disease who undergo liver transplantation are enrolled to the study and receive extensive immune monitoring before and at 1, 2, 3, 4 weeks and 3, 6, 12 months after transplantation, and whenever a clinically indicated liver biopsy is scheduled. Blood samples are analyzed for immune cell numbers and circulating levels of cytokines, chemokines and factors of angiogenesis reflecting immune cell activation. Statistical analysis will focus on the identification of trajectorial patterns of immune reactivity predictive for systemic non-inflammatory states, infectious complications or BPAR using joint modelling approaches.

Discussion

The ChilSFree study will help to understand the immune response after pLTx in different states of infection or rejection. It may provide insight into response mechanisms eventually facilitating immune tolerance towards the graft. Our analysis may yield an applicable immune panel for non-invasive early detection of acute cellular rejection, with the prospect of individually tailoring immunosuppressive therapy. The international collaborative set-up of this study allows for an appropriate sample size which is otherwise difficult to achieve in the field of pediatric liver transplantation.

In vitro intracellular IFNγ, IL-17 and IL-10 producing T cells correlates with the occurrence of post-transplant opportunistic infection in liver and kidney recipients

AIM

To validate intracellular cytokine production functional assay as means of cell-mediated immunity monitoring of post-transplant patients with opportunistic infection (OI).

METHODS

Intracellular cytokine-producing CD4⁺ and CD8⁺ T-cell monitoring was carried out in 30 liver transplant (LTr) and 31 kidney transplant (KTr) recipients from 2010 to 2012. Patients were assessed in our Department of Immunology at the Clinical University ‘Hospital Virgen de la Arrixaca-IMIB’ in Murcia, Spain for one year following transplantation. FACS Canto II flow cytometer was employed to quantify the intracellular production of IL-17, IFNγ and IL-10 cytokines on stimulated CD4⁺CD69⁺ and CD8⁺CD69⁺ T cells and BD FACS DIVA v.6 software was used to analysed the data. Statistical analysis was carried out using SPSS 22.0.

RESULTS

LTr with OI had significantly lower % of CD8⁺CD69⁺IFNγ⁺ T cells at 60 (7.95 ± 0.77 vs 26.25 ± 2.09, P < 0.001), 90 (7.47 ± 1.05 vs 30.34 ± 3.52, P < 0.001) and 180 (15.31 ± 3.24 vs 24.59 ± 3.28, P = 0.01) d post-transplantation. Higher % of CD4⁺CD69⁺IL-10⁺ as well as CD4⁺CD69⁺IL-17⁺ T cells were yet reported at 30 (14.06 ± 1.65 vs 6.09 ± 0.53, P = 0.0007 and 4.23 ± 0.56 vs 0.81 ± 0.14, P = 0.005; respectively), 60 (11.46 ± 1.42 vs 4.54 ± 0.91, P = 0.001 and 4.21 ± 0.59 vs 1.43 ± 0.42, P = 0.03; respectively) and 90 d (16.85 ± 1.60 vs 4.07 ± 0.63, P < 0.001 and 3.97 ± 0.43 vs 0.96 ± 0.17, P = 0.001). Yet, KTr with OI had significantly lower percentage of CD4⁺CD69⁺IFNγ⁺ at 30 (11.80 ± 1.59 vs 20.64 ± 3.26, P = 0.035), 60 (11.19 ± 1.35 vs 15.85 ± 1.58, P = 0.02), 90 (11.37 ± 1.42 vs 22.99 ± 4.12, P = 0.028) and 180 (13.63 ± 2.21 vs 21.93 ± 3.88, P = 0.008) d post-transplantation as opposed to CD4⁺CD69⁺IL-10⁺ and CD8⁺CD69⁺IL-10⁺ T cells which percentages were higher at 30 (25.21 ± 2.74 vs 8.54 ± 1.64, P < 0.001 and 22.37 ± 1.35 vs 17.18 ± 3.54, P = 0.032; respectively), 90 (16.85 ± 1.60 vs 4.07 ± 0.63, P < 0.001 and 23.06 ± 2.89 vs 10.19 ± 1.98, P = 0.002) and 180 (21.81 ± 1.72 vs 6.07 ± 0.98, P < 0.001 and 19.68 ± 2.27 vs 10.59 ± 3.17, P = 0.016) d post-transplantation. The auROC curve model determined the most accurate cut-off values to stratify LTr and KTr at high risk of OI and Cox Regression model confirmed these biomarkers as the most significant risk factors to opportunistic infection.

CONCLUSION

Post-transplant percentages of T-cell subsets differed significantly amongst infected- and non-infected-LTr and -KTr and yet this imbalance was found to contribute towards a worst clinical outcome.

Evaluation of TH17 and TH1 Immune Response Profile in Patients After Renal Transplant

BACKGROUND

Renal transplantation (RT) is the best treatment option for patients with end-stage renal disease (ESRD) because it improves both quality of life and survival. However, allograft rejection remains the most important barrier to successful transplantation. Underlying immunologic mechanisms should be understood to develop appropriate treatment strategies.

METHODS

In this prospective study, we followed renal transplant recipients for 6 months. The study population comprised 50 recipients of renal transplants, and these were divided into 2 groups: 44 patients with stable graft function (SGF) and 6 patients with rejection (RX). Peripheral blood samples were drawn from patients on the pre-RT day, at post-RT day 7, month 1, and month 6, and on the day of rejection for analysis of the percentages of cytokines interleukin (IL) 17 and interferon (IFN) γ with the use of flow cytometry and enzyme-linked immunosorbent assay.

RESULTS

The percentages of intracellular IFN-γ were not significant in the group with RX compared with SGF. Levels of intracellular IL-17 obtained at the 6th month after RT were significantly higher in the RX group than in the SGF group. Plasma levels of pre-RT IL-17 were also higher in the RX group; therefore, it may be a predictive biomarker of acute rejection of renal transplants.

CONCLUSIONS

The present study provides information about pre-RT and post-RT cytokine profiles of Turkish patients with ESRD. We consider cytokine analysis to be a valuable biomarker panel in the prevention of rejection and in assisting with new treatment strategies for patients undergoing renal transplant.

Barcelona Consensus on Biomarker-Based Immunosuppressive Drugs Management in Solid Organ Transplantation

With current treatment regimens, a relatively high proportion of transplant recipients experience underimmunosuppression or overimmunosuppression. Recently, several promising biomarkers have been identified for determining patient alloreactivity, which help in assessing the risk of rejection and personal response to the drug; others correlate with graft dysfunction and clinical outcome, offering a realistic opportunity for personalized immunosuppression. This consensus document aims to help tailor immunosuppression to the needs of the individual patient. It examines current knowledge on biomarkers associated with patient risk stratification and immunosuppression requirements that have been generally accepted as promising. It is based on a comprehensive review of the literature and the expert opinion of the Biomarker Working Group of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology. The quality of evidence was systematically weighted, and the strength of recommendations was rated according to the GRADE system. Three types of biomarkers are discussed: (1) those associated with the risk of rejection (alloreactivity/tolerance), (2) those reflecting individual response to immunosuppressants, and (3) those associated with graft dysfunction. Analytical aspects of biomarker measurement and novel pharmacokinetic-pharmacodynamic models accessible to the transplant community are also addressed. Conventional pharmacokinetic biomarkers may be used in combination with those discussed in this article to achieve better outcomes and improve long-term graft survival. Our group of experts has made recommendations for the most appropriate analysis of a proposed panel of preliminary biomarkers, most of which are currently under clinical evaluation in ongoing multicentre clinical trials. A section of Next Steps was also included, in which the Expert Committee is committed to sharing this knowledge with the Transplant Community in the form of triennial updates.

T-Cell Cytokines as Predictive Markers of the Risk of Allograft Rejection

Over the last decade, several biomarkers and surrogate markers have surfaced as promising predictive markers of risk of rejection in solid organ transplantation. The monitoring of these markers can help to improve graft and recipient care by personalizing immunomodulatory therapies. The complex immune system response against an implanted graft can change during long-term follow-up, and the dynamic balance between effector and regulatory T-cell populations is a crucial factor in antidonor response, risk of rejection, and immunosuppression requirements. Therefore, at any time before and after transplantation, T-effector activity, which is associated with increased production and release of proinflammatory cytokines, can be a surrogate marker of the risk of rejection and need for immunosuppression. In addition, immunosuppressive drugs may have a different effect in each individual patient. The pharmacokinetics and pharmacodynamics of these drugs show high interpatient variability, and pharmacodynamic markers, strongly associated with the specific mechanism of action, can potentially be used to measure individual susceptibility to a specific immunosuppressive agent. The monitoring of a panel of valid biomarkers can improve patient stratification and the selection of immunosuppressive drugs. After transplantation, therapy can be adjusted based on the prediction of rejection episodes (maintained alloreactivity), the prognosis of allograft damage, and the individual's response to the drugs. This review will focus on current data indicating that changes in the T-cell production of the intracellular cytokines interferon-γ and interleukin-2 could be used to predict the risk of rejection and to guide immunosuppressive therapy in transplant recipients.

Analytical Aspects of the Implementation of Biomarkers in Clinical Transplantation

In response to the urgent need for new reliable biomarkers to complement the guidance of the immunosuppressive therapy, a huge number of biomarker candidates to be implemented in clinical practice have been introduced to the transplant community. This includes a diverse range of molecules with very different molecular weights, chemical and physical properties, ex vivo stabilities, in vivo kinetic behaviors, and levels of similarity to other molecules, etc. In addition, a large body of different analytical techniques and assay protocols can be used to measure biomarkers. Sometimes, a complex software-based data evaluation is a prerequisite for appropriate interpretation of the results and for their reporting. Although some analytical procedures are of great value for research purposes, they may be too complex for implementation in a clinical setting. Whereas the proof of "fitness for purpose" is appropriate for validation of biomarker assays used in exploratory drug development studies, a higher level of analytical validation must be achieved and eventually advanced analytical performance might be necessary before diagnostic application in transplantation medicine. A high level of consistency of results between laboratories and between methods (if applicable) should be obtained and maintained to make biomarkers effective instruments in support of therapeutic decisions. This overview focuses on preanalytical and analytical aspects to be considered for the implementation of new biomarkers for adjusting immunosuppression in a clinical setting and highlights critical points to be addressed on the way to make them suitable as diagnostic tools. These include but are not limited to appropriate method validation, standardization, education, automation, and commercialization.

Pharmacodynamics of T cell function for monitoring pharmacologic immunosuppression after allogeneic hematopoietic stem cell transplantation

Information on pharmacodynamic monitoring after allogeneic hematopoietic cell transplantation (allo-SCT) to evaluate individual responses to immunosuppressive drugs is scarce. We studied the relationship between a panel of pharmacodynamic markers monitored during the first 3 months after transplant and the occurrence of graft-versus-host disease (GVHD). Lymphocyte activation assessed by intracellular ATP concentration in CD4⁺ T cells, a high percentage of CD8⁺ effector T cells, and a low percentage of CD4⁺ regulatory T (Treg) cells correlated significantly with GVHD. A cutoff value of 0.5 for the CD8⁺ effector T/Treg ratio provided the most accurate diagnosis of GVHD (sensitivity 58.8%, specificity 91%). These pharmacodynamic markers may provide an efficient complement to standard pharmacokinetic monitoring of immunosuppressive drugs after allo-SCT.

Combined Detection of Serum IL-10, IL-17, and CXCL10 Predicts Acute Rejection Following Adult Liver Transplantation

Discovery of non-invasive diagnostic and predictive biomarkers for acute rejection in liver transplant patients would help to ensure the preservation of liver function in the graft, eventually contributing to improved graft and patient survival. We evaluated selected cytokines and chemokines in the sera from liver transplant patients as potential biomarkers for acute rejection, and found that the combined detection of IL-10, IL-17, and CXCL10 at 1-2 weeks post-operation could predict acute rejection following adult liver transplantation with 97% specificity and 94% sensitivity.

Environmental Exposures-The Missing Link in Immune Responses After Transplantation

In transplantation, immunosuppression has been directed at controlling acute responses, but treatment of chronic rejection has been ineffective. It is possible that factors that have previously been unaccounted for, such as exposure to inhaled pollution, ultraviolet light, or loss of the normal equilibrium between the gut immune system and the outside environment may be responsible for shifting immune responses to an effector/inflammatory phenotype, which leads to loss of self-tolerance and graft acceptance, and a shift towards autoimmunity and chronic rejection. Cells of the immune system are in a constant balance of effector response, regulation, and quiescence. Endogenous and exogenous signals can shift this balance through the aryl hydrocarbon receptor, which serves as a thermostat to modulate the response one way or the other, both at mucosal surfaces of interface organs to the outside environment, and in the internal milieu. Better understanding of this balance will identify a target for maintenance of self-tolerance and continued graft acceptance in patients who have achieved a "steady state" after transplantation.

High expression of CD38, CD69, CD95 and CD154 biomarkers in cultured peripheral T lymphocytes correlates with an increased risk of acute rejection in liver allograft recipients

The mayor goal still outstanding into the solid organ transplantation field involves the search of surrogate biomarkers able to predict several clinical events, such as acute rejection (AR) or opportunistic infection. In the present multicenter study, a series of interesting surface antigens with important activator or inhibitory immune functions on cultured peripheral T cells were monitored in liver transplant recipients drawn at baseline and up to one year after transplantation. Sixty-four patients were included in the multicenter study during 3 years. Pre- and post-transplantation surface antigens levels displayed significant differences between AR and non acute rejection (NAR) groups, and also this differential expression was used to construct a risk predictive model based on a composite panel of outcome biomarkers (CD38, CD69, CD95 and CD154). The model was able to stratify these patients at high risk of AR. These preliminary results could provide basic information to improve the immunosuppressive treatment and it might better help to predict AR episodes.

High proportion of CD95(+) and CD38(+) in cultured CD8(+) T cells predicts acute rejection and infection, respectively, in kidney recipients

The aim of this study was to find noninvasive T-cell markers able to predict rejection or infection risk after kidney transplantation. We prospectively examined T-lymphocyte subsets after cell culture stimulation (according to CD38, CD69, CD95, CD40L, and CD25 expression) in 79 first graft recipients from four centers, before and after transplantation. Patients were followed up for one year. Patients who rejected within month-1 (n=10) showed high pre-transplantation and week-1 post-transplantation percentages of CD95(+), in CD4(+) and CD8(+) T-cells (P<0.001 for all comparisons). These biomarkers conferred independent risk for early rejection (HR:5.05, P=0.061 and HR:75.31, P=0.004; respectively). The cut-off values were able to accurately discriminate between rejectors and non-rejectors and Kaplan-Meier curves showed significantly different free-of-rejection time rates (P<0.005). Patients who rejected after the month-1 (n=4) had a higher percentage of post-transplantation CD69(+) in CD8(+) T-cells than non-rejectors (P=0.002). Finally, patients with infection (n=41) previously showed higher percentage of CD38(+) in CD8(+) T-cells at all post-transplantation times evaluated, being this increase more marked in viral infections. A cut-off of 59% CD38(+) in CD8(+) T-cells at week-1, week-2 and month-2 reached 100% sensitivity for the detection of subsequent viral infections. In conclusion, predictive biomarkers of rejection and infection risk after transplantation were detected that could be useful for the personalized care of kidney recipients.

Elevated Circulating Interleukin 33 Levels in Stable Renal Transplant Recipients at High Risk for Cardiovascular Events

Background

The Major Adverse Cardiovascular Events calculator (CRCRTR-MACE) estimates the burden of cardiovascular risk in renal transplant recipients (RTR). Our recent study of 95 RTR reported the 7-year median risk of cardiovascular events (CVE) to be 9.97%, ranging from 1.93 to 84.27%. Nearly a third (28.4%) of the cohort was above 20% risk for a CVE. Since interleukins (ILs) as part of the inflammatory response may play a role in the pathogenesis of cardiovascular disease (CVD), we extended this study to identify which ILs are associated with high cardiovascular risk in this population.

Methods

Twenty-two ILs were measured by multiplexed fluorescent bead-based immunoassay in 95 RTR and 56 normal controls. Stepwise analysis after multivariate determination of significant demographic and inflammatory variables was performed between the high and low-CVD risk groups (which were arbitrarily set at scores <10% and ≥20%, respectively). Normalized data was presented as mean ± SD and non-normalized data as median (minimum–maximum). Significance was measured at <0.05.

Results

27.5% of the low-risk and 31.3% of the high-risk groups had mean IL levels above the 95 percentile of the normal control levels. In the non-parametric analysis IL-6, 9, 16, 17 and 33 were significantly higher in the high-risk group compared to the control. Univariate analysis (UVA) of the high-risk group identified IL-33 as the only IL that remained significantly higher than the control and low-risk groups (p = 0.000). The percentage of patients with IL-33 levels above the 90 percentile of control value in the low and high-risk groups were 15.6% and 52.0%, respectively (p<0.002). UVA of factors significant to high IL-33 levels included estimated glomerular filtration rate (eGFR), while diabetes mellitus, serum phosphorus, microalbuminuria and age also remained significant in the multivariate analysis.

Conclusion

Circulating IL-33 level is positively associated with high CRCRTR-MACE score. Diminished eGFR, age, diabetes, serum phosphorus and microalbuminurea demonstrate significant relationship with elevated IL-33 levels, supporting the possible pathognomonic role of IL-33 in the cardiovascular burden in RTR.