Acute Liver Transplant Rejection Research Articles

Serum Levels of Interleukin-34 During Acute Rejection in Liver Transplantation

IntroductionAccumulating evidence indicates that interleukin (IL)-34 participates in T-cell homeostasis and tolerance due to the ability of IL-34 to trigger apoptosis of Th1, Th17, and Tc1 cells, but spare Th2 cells and Treg. In addition, IL-34 exerts anti-inflammatory effects by impairing leukocyte adhesion and transendothelial migration, and reducing the secretion of proinflammatory cytokines. The aim of our study was to investigate the time course of serum levels of IL-34 during hepatic allograft rejection. MethodsSerum levels of IL-34 were determined in 20 healthy subjects and 45 hepatic transplant recipients. These patients were divided into 2 groups: group I was composed of 15 patients with acute rejection, and group II was composed of 30 patients without acute rejection. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy. ResultsThe concentrations of IL-34 were higher in the rejection group vs nonrejection group during the entire postoperative period. The whole transplant group, including those with stable graft function, showed higher IL-34 serum levels than the controls at all times after liver transplantation. ConclusionsOur preliminary results could be related to the recent finding that IL-34 may play an immune-suppressive role in liver transplantation. In our case, although we must be cautious with serum data, increased IL-34 would help to control alloresponse during rejection and protect from graft lost.

14-bp ins/del polymorphism and +3142C>G SNP of the HLA-G gene have a significant impact on acute rejection after liver transplantation

Expression of human leukocyte antigen G (HLA-G) has been associated with increased graft survival and decreased rejection episodes. It has been described that the HLA-G 14-base pair (bp) insertion/deletion (ins/del) (rs66554220) and +3142C>G (rs1063320) gene polymorphisms modify the expression level of HLA-G. The aim of the study was to investigate whether these HLA-G polymorphisms have an impact on acute rejection after liver transplantation. In total, 146 liver transplant recipients (57 with acute rejection and 89 without acute rejection) and 99 corresponding liver donors were genotyped for both polymorphisms. In liver transplantation the 14-bp ins/ins and the +3142GG genotypes are more frequent in recipients without rejection compared to recipients with rejection (3.5% vs. 31.5%, p=<0.001; 12.3% vs. 41.6%, p=<0.001) demonstrating an association with protection from acute rejection. In contrast, in liver donors we could not reveal an association. We conclude that 14-bp ins/ins and +3142GG genotypes of HLA-G in liver transplant recipients are of importance for prediction of acute rejection after liver transplantation. Thus genotyping of liver recipients for both polymorphisms might be useful to stratify liver transplant recipients according to the risk of acute liver transplant rejection.

Interleukin-10 polymorphism (-1082, G/A) on acute rejection risk in solid organ transplant recipients in a Caucasian population: a meta-analysis

Cytokines may play an important role in the acute rejection (AR) of solid organ transplantation. Many studies have investigated the association between interleukin-10 gene (IL-10) polymorphisms and risk of AR. The aim of this study was to determine the relationship between IL-10 polymorphism (-1082, G/A) and AR risk after solid organ transplantation in Caucasian population. A comprehensive electronic search of PUBMED, Google Scholar, and Korean databases was performed. Meta-analysis was performed using comprehensive meta-analysis software (Biostat, NJ,USA). We assessed the pooled p-value, odds ratio (OR), and 95% confidence interval (CI) to measure the association between the risk of AR and IL-10 polymorphism (-1082, G/A). The OR and 95% CI were used to evaluate the strength of the association. P-values less than 0.05 were considered statistically significant. Fourteen case-control studies were included in this meta-analysis. In overall analysis, we observed that IL-10 polymorphism (-1082, G/A) was associated with the AR in liver transplantation (G allele vs. A allele, OR = 1.436, 95% CI = 1.006-2.050, p = 0.046 in fixed model). However, IL-10 polymorphism (-1082, G/A) did not show any significant association with solid organ transplantation and renal transplantation (p&gt;0.05 in each model, respectively). Our meta-analysis suggests that IL-10 polymorphism (-1082, G/A) may be related to susceptibility of AR in liver transplantation recipients.

Profiling immunologic risk for acute rejection in liver transplantation: Recipient age is an important risk factor

BackgroundCareful management of induction and maintenance of immunosuppression is paramount to prevent acute rejection in liver transplantation. A methodical analysis of risk factors for acute cellular rejection may provide a more comprehensive method to profile the immunologic risk of candidates. MethodsUsing registry data from the Organ Procurement and Transplantation Network (OPTN), we identified 42,508 adult recipients who underwent orthotopic liver transplant (OLT) between 2002 and 2013. We excluded recipients with a blank entry for treated rejection. We analyzed this all inclusive cohort in addition to a subset of 27,493 patients with just tacrolimus immunosuppression. Multivariate logistic regression was used on both cohorts and identified independent risk factors for treated acute rejection at one year. ResultsRecipient age (reference group was 40 to 60years) was a dominant risk factor for rejection in both cohorts and had a dose response relationship. The strongest risk factors in the inclusive cohort were: age 18–25 (OR 2.20), age 26–29 (OR 2.03), and primary biliary cholangitis (OR 1.55). The most protective factors were age 70 and older (OR 0.68), and age 65–69 (OR 0.70). The rates of rejection had a similar pattern. ConclusionsAlthough prior studies have suggested age as a risk factor for rejection in liver transplantation, this is the first study of national-level data to demonstrate a robust dose dependent relationship between age and risk for rejection at one year. Clinicians should place significant weight on recipient age when they assess their recipients for the immunologic risk of rejection.

Usefulness of liver stiffness measurement during acute cellular rejection in liver transplantation.

Liver stiffness measurement (LSM) is a useful method to estimate liver fibrosis and portal hypertension. The inflammatory process that takes place in post-liver transplant acute cellular rejection (ACR) may also increase liver stiffness. We aimed to explore the association between liver stiffness and the severity of ACR, as well as to assess the relationship between liver stiffness and response to rejection treatment in a prospective study that included 27 liver recipients with biopsy-proven ACR, 30 stable recipients with normal liver tests, and 30 hepatitis C virus (HCV)-infected LT recipients with histologically diagnosed HCV recurrence. Patients with rejection were stratified into 2 groups (mild and moderate/severe) according to the severity of rejection evaluated with the Banff score. Routine biomarkers and LSM with FibroScan were performed at the time of liver biopsy (baseline) and at 7, 30, and 90 days in patients with rejection and at baseline in control patients. Median baseline liver stiffness was 5.9 kPa in the mild rejection group, 11 kPa in the moderate/severe group (P = 0.001), 4.2 kPa in stable recipients (P = 0.02 versus mild rejection), and 13.6 kPa in patients with recurrent HCV (P = 0.17 versus moderate/severe rejection). The area under the receiver operator characteristic curve of LSM to discriminate mild versus moderate/severe ACR was 0.924, and a LSM value of 8.5 kPa yielded a positive predictive value of 100% to diagnose moderate/severe rejection. Liver stiffness improved in 7%, 21%, and 64% of patients with moderate/severe rejection at 7, 30, and 90 days. In conclusion, according to the results of this exploratory study, LSM is associated with the severity of ACR in liver transplantation and thus may be of help in its assessment.

Molecular Characterization of Acute Cellular Rejection Occurring During Intentional Immunosuppression Withdrawal in Liver Transplantation

Acute cellular rejection occurs frequently during the first few weeks following liver transplantation. During this period, its molecular phenotype is confounded by peri- and postoperative proinflammatory events. To unambiguously define the molecular profile associated with rejection, we collected sequential biological specimens from 55 patients at least 3 years after liver transplantation who developed rejection during trials of intentional immunosuppression withdrawal. We analyzed liver tissue and blood samples obtained before initiation of drug withdrawal and at rejection, alongside blood samples collected during the weaning process. Gene expression profiling was conducted using whole-genome microarrays and real-time polymerase chain reaction. Rejection resulted in distinct blood and liver tissue transcriptional changes in patients who were either positive or negative for hepatitis C virus (HCV). Gene expression changes were mostly independent from pharmacological immunosuppression, and their magnitude correlated with severity of histological damage. Differential expression of a subset of genes overlapped across all conditions. These were used to define a blood predictive model that accurately identified rejection in HCV-negative, but not HCV-positive, patients. Changes were detectable 1-2 mo before rejection was diagnosed. Our results provide insight into the molecular processes underlying acute cellular rejection in liver transplantation and help clarify the potential utility and limitations of transcriptional biomarkers in this setting.

Activated Regulatory T Cells Expressing CD4+CD25highCD45RO+CD62L+ Biomarkers Could Be a Risk Factor in Liver Allograft Rejection

Activated regulatory T cells (aTregs) are nowadays a hot topic in organ transplantation to establish their role during acute rejection (AR) episodes. The aim of this multi-center study was to monitor the frequency of aTregs within the first year after transplantation in a cohort of first-time liver transplant recipients enrolled from 2010 to 2012. aTregs frequency was analyzed by means of flow cytometry. Patients who had AR showed higher levels of aTregs during first year after transplantation in comparison with patients who did not have higher levels. High levels of aTregs in liver recipients might be used as a biomarker of AR; however, further studies must be done to address the potential role of aTregs as biomarkers of AR in liver transplantation.

Late acute rejection in liver transplant: a systematic review.

Introduction: Late acute rejection leads to worse patient and graft survival after liver transplantation. Aim: To analyze the reported results published in recent years by leading transplant centers in evaluating late acute rejection and update the clinical manifestations, diagnosis and treatment of liver transplantation. Method: Systematic literature review through Medline-PubMed database with headings related to late acute rejection in articles published until November 2013 was done. Were analyzed demographics, immunosuppression, rejection, infection and graft and patient survival rates. Results: Late acute rejection in liver transplantation showed poor results mainly regarding patient and graft survival. Almost all of these cohort studies were retrospective and descriptive. The incidence of late acute rejection varied from 7-40% in these studies. Late acute rejection was one cause for graft loss and resulted in different outcomes with worse patient and graft survival after liver transplant. Late acute rejection has been variably defined and may be a cause of chronic rejection with worse prognosis. Late acute rejection occurs during a period in which the goal is to maintain lower immunosuppression after liver transplantation. Conclusion: The current articles show the importance of late acute rejection. The real benefit is based on early diagnosis and adequate treatment at the onset until late follow up after liver transplantation.

Role of the Fyn −93A>G polymorphism (rs706895) in acute rejection after liver transplantation

The tyrosine kinase Fyn phosphorylates tyrosine residues on key targets involved in early T-cell signal transduction. T-cell signal transduction is one essential step for acute transplant rejection. The aim of this study was to evaluate the association of Fyn −93A>G single nucleotide polymorphism (SNP) (rs706895) with the susceptibility to acute rejection episodes in liver transplantation. In total, 72 liver transplant recipients with one biopsy proven acute rejection (S-BPAR), 56 with multiple BPAR (M-BPAR), 105 without BPAR (No-BPAR), and 145 healthy controls were enrolled in this case-control study. The SNP was genotyped by polymerase chain reaction–allele specific restriction enzyme analysis (PCR–ASRA) and was analyzed for a recessive and a dominant model. The Fyn −93G allele exhibits in healthy controls a statistically significant lower frequency than in liver recipients (18% vs. 24%; p=0.046) or in liver recipients with BPAR (18% vs. 27%; p=0.017). However, the genotype and allele frequencies of the Fyn −93A>G SNP demonstrate no significant differences between recipients with acute rejection episodes (S-BPAR and M-BPAR) and No-BPAR recipients. Thus our results provide no evidence that the Fyn −93A>G SNP contributes to the susceptibility to acute liver transplant rejection in a Caucasian population.

Hepatobiliary Quiz (Answers)—15 (2015)

Hepatobiliary Quiz (Answers)—15 (2015)

Role of IL-21 signaling pathway in transplant-related biology.

Since pro-inflammatory cytokine IL-21 and its receptor (IL-21R) are closely involved in regulating both innate and adaptive immune responses, it is conceivable that they may play important roles in the field of organ transplantation. IL-21/IL21-R regulates immune activities of CD8+ T cells, Tfh cells, Th17 cells, B cells, NK cells, dendritic cells and stimulates dendritic cells to produce high level of IL-6, TNF-alpha, and CCL2. However, their roles and underlying mechanisms remain obscure. Our present study is the first describing the role of IL-21 signaling pathway in transplant biology. It was found that IL-21/IL-21R signaling pathways contribute to the processes of ischemia/reperfusion and acute rejection of liver or kidney transplantation. IL-21 is capable of regulating B cell function and immunoglobulin production, driving CD8+ T cell expansion, regulating Th17 and dendritic cell function. Deficiency of IL-21 may cause autoimmunity and infectious disease in clinical-scenario patients. It is known that CD8+ T cells, Th17, and dendritic cells are closely involved in cardiac transplant tolerance. Our own original experimental research on mouse cardiac transplantation manifested that allograft survival could be significantly prolonged in the IL-21R deficient recipients. All these can deepen our understanding of immunobiological role of IL-21 and its receptor in the field of transplantation. Intervention of IL-21 signaling pathway may apparently regulate immunoresponses in vivo, which can be subsequently utilized as a therapeutic strategy in clinic.

Markers of acute rejection and graft acceptance in liver transplantation.

The evaluation of the immunosuppression state in liver transplanted patients is crucial for a correct post-transplant management and a major step towards the personalisation of the immunosuppressive therapy. However, current immunological monitoring after liver transplantation relies mainly on clinical judgment and on immunosuppressive drug levels, without a proper assessment of the real suppression of the immunological system. Various markers have been studied in an attempt to identify a specific indicator of graft rejection and graft acceptance after liver transplantation. Considering acute rejection, the most studied markers are pro-inflammatory and immunoregulatory cytokines and other proteins related to inflammation. However there is considerable overlap with other conditions, and only few of them have been validated. Standard liver tests cannot be used as markers of graft rejection due to their low sensitivity and specificity and the weak correlation with the severity of histopathological findings. Several studies have been performed to identify biomarkers of tolerance in liver transplanted patients. Most of them are based on the analysis of peripheral blood samples and on the use of transcriptional profiling techniques. Amongst these, NK cell-related molecules seem to be the most valid marker of graft acceptance, whereas the role CD4+CD25+Foxp3+ T cells has still to be properly defined.

Lack of association between CD40 polymorphisms and acute rejection in German liver transplant recipients

CD40 and its ligand, CD154, are major costimulatory molecules whose interactions are important in alloreactive transplant rejection. The aim of this study was to examine the association of CD40 polymorphisms with the susceptibility to acute rejection episodes in liver transplantation. In total, 112 liver transplant recipients with biopsy proven acute rejections (BPAR), 97 without BPAR (WBPAR), and 112 healthy control individuals were enrolled in the study. Two single nucleotide polymorphisms (SNPs) of CD40 gene (rs1883832 and rs4810485) were genotyped by polymerase chain reaction-allele specific restriction enzyme analysis (PCR-ASRA). Both SNPs has been tested for a recessive and a dominant model. No significant differences were found in the genotype and allele frequencies of the SNPs rs1883832 and rs4810485 between BPAR liver recipients and WBPAR recipients. Our results do not suggest an important role of tested CD40 SNPs in the susceptibility to acute liver transplant rejection in a Caucasian population.

Impact of cytochrome P450 3A5 polymorphism in graft livers on the frequency of acute cellular rejection in living-donor liver transplantation.

We investigated whether the cytochrome P450 3A5*3 (CYP3A5*3) genotype affects tacrolimus pharmacokinetics and the risk of acute cellular rejection in living-donor liver transplant patients in Japan. Between July 2004 and June 2011, we enrolled 410 living-donor liver transplant patients receiving tacrolimus. Biopsy specimens of intestinal mucosa and graft liver at surgery were obtained to examine the mRNA expression of CYP3A subfamilies as well as the genotyping of CYP3A5*3 polymorphism. The CYP3A5 genotype in the native intestine had no significant effect on the occurrence of acute cellular rejection between postoperative days 14 and 23 in cases with identical or compatible ABO blood types (11.5% for the CYP3A5*1 allele vs. 7.4% for CYP3A5*3/*3; P=0.2643), although the concentration/dose ratio of tacrolimus was significantly higher in patients with the intestinal CYP3A5*3/*3 genotype than in those with the CYP3A5*1 allele for 5 post-transplant weeks. However, patients who received a graft liver with the CYP3A5*1 allele showed a higher rate of acute cellular rejection than those who received a graft liver with the CYP3A5*3/*3 genotype (14.5 vs. 5.7%; P=0.0134). The relative risk for acute cellular rejection associated with the CYP3A5*1 liver allele was 2.629 (P=0.018, Cox regression model). Consequently, graft liver CYP3A5*1 genotype might increase the risk for acute cellular rejection after living-donor liver transplantation, possibly by associating with the local hepatic tacrolimus concentration. The target level of tacrolimus may be affected by the CYP3A5*3 genotype of the liver, rather than by that of the small intestine, after postoperative day 14.

Genetic polymorphism of interferon regulatory factor 5 (IRF5) correlates with allograft acute rejection of liver transplantation.

BackgroundAlthough liver transplantation is one of the most efficient curative therapies of end stage liver diseases, recipients may suffer liver graft loss opst-operation. IRF-5, a member of Interferon Regulatory Factors, functions as a key regulator in TLR4 cascade, and is capable of inducing inflammatory cytokines. Although TLR4 has been proved to contribute to acute allograft rejection, including after liver transplantation, the correlation between IRF5 gene and acute rejection has not been elucidated yet.MethodsThe study enrolled a total of 289 recipients, including 39 females and 250 males, and 39 recipients developed acute allograft rejection within 6 months post-transplantation. The allograft rejections were diagnosed by liver biopsies. Genome DNA of recipients was extracted from pre-operative peripheral blood. Genotyping of IRF-5, including rs3757385, rs752637 and rs11761199, was performed, followed by SNP frequency and Hardy-Weinberg equilibrium analysis.ResultsThe genetic polymorphism of rs3757385 was found associated with acute rejection. G/G homozygous individuals were at higher risk of acute rejection, with a P value of 0.042 (OR = 2.34 (1.07–5.10)).ConclusionsIRF5, which transcriptionally activates inflammatory cytokines, is genetically associated with acute rejection and might function as a risk factor for acute rejection of liver transplantations.

MicroRNA expression in the acute rejection of liver transplantation in rats

Objective To investigate the role of miRNA expression in the acute rejection of liver transplantation in rats.Methods The rat orthotopic liver transplantation (ROLT) was performed using the two-cuff technique described by Kamada with modification.Rats were randomly divided into two groups,a rejection group (n=12) and a control group (n=12).MicroRNA microarray technology was used to screen the microRNA expression profile in peripheral blood on the 7th postoperative day,and the bioinformatics microRNA screening method detected that miR-206 had the biggest difference in expression level.Peripheral blood samples were gathered before,3 days,5 days,and 7 days after ROLT to analyze the expression level of miR 206 quantitatively with qRT PCR technology.Dynamic contrast analysis was made between the quantitative results of miR-206 and the results of pathological examination and liver function tests.Results There was no significant difference in miR-206 expression level between the rejection group and control group before the operation (t=0.105,P=0.921).MiR-206 expression was significantly higher in the rejection group than in the control group 3 days after ROLT (t=8.875,P=0.001).The expression level of miR 206 in the rejection group also increased gradually over time (F=32.154,P＜0.01).However,pathological changes and liver function index did not show obvious differences until the 5th and 7th day postoperatively.The expression of miR-206 in peripheral blood and graft was strongly and positively correlated with the rejection active index (RAI) of acute liver rejection pathology (0.812 and 0.881 respectively,P＜0.01).In the rejection group,the miR-206 level in peripheral blood and graft were positively associated with each other.Conclusions Detection of miR-206 in peripheral blood was significantly better than pathological examination and liver function test in the diagnosis of acute rejection of rat liver transplantation.Moreover,miR-206 was an early sensitive and specific marker for making this diagnosis. Key words: MicroRNA; Liver transplantation; Rat; Acute rejection

Management of Acute Rejection in Paediatric Liver Transplantation

The success of paediatric liver transplantation is attributed to improved surgical techniques and the advent of calcineurin inhibitor-based immunosuppression. Acute rejection (AR) rarely results in graft loss with calcineurin inhibitor immunosuppressive regimens, and the advent of newer agents like interleukin (IL)-2 receptor antibodies. The latter have the benefit of reducing the incidence of AR further and may be of use in patients who are susceptible to recurrent AR, were retransplanted for graft rejection or are in a steroid-sparing regimen. A total of 60% of all paediatric liver transplants result in AR; however, there is a 75% response rate to initial steroid therapy. Steroid therapy remains the mainstay of initial AR management, coupled with an increase in baseline immunosuppression. Steroid-resistant rejection (SRR), previously an immediate indication for potent anti-lymphocyte preparations, is now effectively treated with chimeric or humanised IL-2 receptor monoclonal antibodies. Recurrent AR can be treated by adding adjuvant immunosuppressive agents such as mycophenolate mofetil (MMF) or sirolimus. Studies have also demonstrated the efficacy of MMF as rescue therapy for SRR. Anti-lymphocyte preparations such as anti-thymocyte globulin (ATG) and OKT3 are rarely used in SRR but may be of use as rescue therapy for severe SRR. The challenges of the management of AR remain in the management of recurrent AR and SRR. We discuss the pathogenesis, diagnosis and management of AR, including prevention, and specific management of AR and SRR based on current evidence and our own experience at the King's College Paediatric Liver, Gastroenterology and Nutrition Centre in London.

Lack of association between CTLA-4 and PDCD1 polymorphisms and acute rejection in German liver transplant recipients

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell-death 1 (PDCD1) are two genes encoding coinhibitory immunoreceptors that are involved in regulation transplant rejection and tolerance induction. Thus, CTLA-4 and PDCD1 may be good candidate genes to evaluate in liver transplant rejection. In this retrospective study, we investigated whether four functional single nucleotide polymorphisms (SNP) of the CTLA-4 gene and PDCD1 gene were associated with susceptibility to liver transplant rejection. The SNPs -1772T>C (rs733618), -1661A>G (rs4553808) of the CTLA-4 gene, and the SNPs 7146G>A (rs11568821), 7209C>T (rs41386349) of the PDCD1 gene were genotyped by polymerase chain reaction allele specific restriction enzyme analysis (PCR-ASRA) in 100 liver recipients with acute rejection, 104 liver transplant recipients without acute rejection and 100 healthy control individuals. For the selected SNPs we did not detect any significant difference in genotypic and allelic frequencies between liver transplant recipients with and without acute rejection. In conclusion, our results suggest that the tested SNPs may not be associated with susceptibility to acute liver transplant rejection in a Caucasian population.

Serum protein biomarkers for acute rejection in liver transplantation

Introduction: Although 20–40% of patients experience at least one episode of acute rejection (AR) after liver transplantation (LTx), diagnosis of AR is still mainly based on tissue analysis from liver biopsies. Biomarkers in routinely taken blood samples would be a powerful non-invasive tool for monitoring of the liver graft status. The aim of this study was to investigate the diagnostic and prognostic value of serum protein biomarkers for acute rejection in LTx recipients.

The holy grail: a biomarker for acute rejection in liver transplantation

DOI of original article: 10.1016/j.jss.2012.0 * Corresponding author. Division of Transpla Street, Jackson, MS 39216. Tel.: þ1 601 518 3 E-mail address: cdanderson@umc.edu (C 0022-4804/$ e see front matter a 2013 Elsev http://dx.doi.org/10.1016/j.jss.2012.08.058 The National Institutes of Health defines a biomarker as a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathologic processes, and pharmacologic responses to intervention [1]. Numerous biomarkers are employed in current medical management, such as blood glucose in diabetes, creatinine levels for renal failure, and troponin levels with acute myocardial infarction. To be clinically useful, a biomarker must have ease of testing, relatively low cost, and widely available assay techniques with good reproducibility, adequate sensitivity, and high specificity. In addition, the ideal biomarker can be obtained with minimal invasiveness. Traditionally, candidate biomarkers were generally studied through hypothesis-driven approaches by selecting targets based on their postulated pathophysiologic role. More recently, advances in genomic and proteomic technologies have allowed analysis of a large number of candidate biomarkers in a relatively short amount of time. These techniques of discovery are also relatively free of investigator bias. These new high-throughput analytical tools provide the means to identify new biomarkers in all areas of medicine