Rejection In Liver Transplantation Research Articles

Analysis of the Association between the Tgfb1 Gene Haplotype and Liver Diseases in Children.

Transforming growth factor-β1 (TGF-β1), a cytokine with immunosuppressive and pro-fibrogenic activity, is a potential marker of infection, liver transplant rejection, and fibrosis. Its levels in the blood and tissues depend on many factors; however, the role of gene polymorphism is still unclear. In this work, the distribution frequency of three single nucleotide polymorphism (SNP) variants of the Tgfb1 gene, namely rs1800469, rs1800470, and rs1800471, was studied in children with end-stage liver disease (ESLD). The study included 225 pediatric liver recipients aged 1 month to 16 years (median, 8 months), including 100 boys and 125 girls, and 198 healthy individuals aged 32.7 ± 9.6 years, including 78 men and 120 women. The indication for liver transplantation in children was ESLD, which was mostly caused by congenital and inherited liver diseases. SNPs were detected by real-time polymerase chain reaction using TaqMan probes and DNA isolated from peripheral blood. SNP frequency distribution was in Hardy-Weinberg equilibrium and did not differ between children with liver diseases and the healthy ones. Analysis of the SNPs frequency based on allelic interaction models did not reveal any differences between patients and the healthy individuals. Evaluation of linkage disequilibrium for Tgfb1 polymorphic variant pairs revealed a statistically significant linkage between all studied variants. Seven haplotypes, which are variants of SNP combinations, were observed in the studied groups of patients and healthy individuals. A total of 80% of the group had three haplotypes, whose frequencies did not differ between patients and the healthy individuals. Significant differences were found in the frequency of the haplotypes A-A-C, G-G-C, and G-A-G (at rs1800469, rs1800470, and rs1800471, respectively), which were observed up to 11 times more often in recipients compared to the healthy individuals. It is possible that these haplotypes are ESLD-predisposing variants, which may also contribute to the development of complications after liver transplantation in children.

Dendritic cells in liver transplantation immune response.

Dendritic cells (DCs) are the most powerful antigen presenting cells (APCs), they are considered one of the key regulatory factors in the liver immune system. There is currently much interest in modulating DC function to improve transplant immune response. In liver transplantation, DCs participate in both the promotion and inhibition of the alloreponse by adopting different phenotypes and function. Thus, in this review, we discussed the origin, maturation, migration and pathological effects of several DC subsets, including the conventional DC (cDC), plasmacytoid DC (pDC) and monocyte-derived DC (Mo-DC) in liver transplantation, and we summarized the roles of these DC subsets in liver transplant rejection and tolerance. In addition, we also outlined the latest progress in DC-based related treatment regimens. Overall, our discussion provides a beneficial resource for better understanding the biology of DCs and their manipulation to improve the immune adaptability of patients in transplant status.

The dynamic TRβ/IGH CDR3 repertoire features in patients with liver transplantation

ObjectiveAt present, little is known about the immune mechanism of liver transplantation caused by decompensated cirrhosis. Lymphocytes play an essential important role in the immune rejection of liver transplantation. In this study, we aimed to comprehensively analyze changes in complementary determinant 3 (CDR3) repertoire of T cell receptor β chain (TRβ) and immunoglobulin heavy chain (IGH) in liver transplantation patients and healthy controls (HC). MethodsHigh-throughput sequencing technology was used to study the characteristics of TRβ/IGH CDR3 repertoire, and identify the amino acid sequences of TRβ and IGH associated with liver transplantation patients and HC. ResultsWe found that some TRβ and IGH CDR3 repertoire characteristics differed between liver transplant patients and HC. The diversity of TRβ CDR3 increased in the liver transplantation group. First and seven days after live transplantation patients showed a lower degree of T cell clone amplification compared to the HC group. The CDR3 repertoire of the TRβ/IGH chain was certainly biased in the use of some V, D, and J gene segments, TRβ/IGH V-J combined frequency was also skewed and TRβ CDR3 clonotypes were shared at a higher degree in the liver transplantation patients. Importantly, one amino acid sequence in the decompensated cirrhosis group was significantly higher than that in the healthy group. It should be noted that the frequency of some CDR3 sequences is closely correlated with the different stages of liver transplantation, and these sequences may play a key role in liver transplantation. ConclusionBased on the above results, we can better understand the dynamic changes of TCβ/IGH CDR3 repertoire in patients during liver transplantation.

Successful treatment of acute antibody-mediated rejection of liver allograft with imlifidase: A case report

Although the incidence of acute antibody mediated rejection in liver transplantation is low, the consequences of acute antibody mediated rejection can be devastating, often leading to severe fibrotic changes and early graft loss. Conventional treatment modalities for management of moderate-to-severe acute antibody mediated rejection in liver transplant continue to rely on of corticosteroids, plasmapheresis, and intravenous immunoglobulin. However, management of refractory, severe antibody mediated rejection remains without a clear gold-standard approach. This case report describes successful first use of Imlifidase, an Ig-G degrading enzyme, for management of acute refractory antibody mediated rejection following orthotopic liver transplant. This 41-year-old woman developed acute antibody meditated rejection and donor specific antibodies within two weeks of undergoing an A2 to O liver transplant. Following unsuccessful treatment with conventional modalities, treatment with Imlifidase resulted in normalization of liver function, resolution of antibody mediated rejection on surveillance biopsy, and disappearance of donor specific antibodies. Imlifidase could represent a promising treatment for refractory antibody mediated rejection in liver transplantation and warrants further study.

Reply: Acute rejection in liver transplantation: Time for uniform definitions.

Reply: Acute rejection in liver transplantation: Time for uniform definitions.

Effectiveness and safety outcomes in patients with EBV+ PTLD treated with allogeneic EBV-specific T-cell immunotherapy (tabelecleucel) under an expanded access program (EAP) in Europe.

7521 Background: Pts with relapsed or refractory (r/r) EBV+ post-transplant lymphoproliferative disease (PTLD) in Europe have had historically poor overall response rates and median overall survival (OS) with no approved treatment options. Tabelecleucel, an off-the-shelf, allogeneic EBV-specific T-cell immunotherapy has shown clinical benefit and favorable safety profile in the treatment of EBV+ PTLD failing rituximab ± chemotherapy (Prockop EBMT 2021, ATC 2021, ASH 2022). Its recent European marketing authorization (EMA) represents the first approval of an allogenic T-cell immunotherapy globally. Methods: Atara Bio supported expanded access requests for tabelecleucel in Europe. Here we report updated effectiveness and safety data for r/r EBV+ PTLD pts who provided consent for research between Sep 2020 and Dec 2022. Results: 74 EAP requests were received from 10 countries for pts with r/r EBV+ diseases. 27 EBV+ PTLD pts consented to secondary use of data and 24 pts had received ≥1 dose of tabelecleucel, including 4 pts with primary central nervous system (PCNS) PTLD. 16 of 24 (66.7%) PTLD pts achieved a partial (PR) (33.3%) or complete (CR) (33.3%) response, with median time to response (TTR) of 1.0 mo (0.8–2.2). Response rate for PCNS PTLD pts was 75% (1 CR, 2 PR). 1-yr OS Kaplan–Meier (KM) estimate rates were 73.7% (95% CI: 47.3, 88.3) overall, 87.5% in allogeneic hematopoietic stem cell transplant (HCT) and 66.5% in solid organ transplant (SOT), with a median follow-up time of 9.9 (2.4–13.9) and 6.0 (0.7–18.0) mo, respectively. Serious treatment-emergent adverse events (TESAEs) were reported in 7 (29.2%) pts, including 1 fatal event of disease progression. Predefined risks for tabelecleucel were reported in 3 pts; 1 (4.2%) SOT pt had a TESAE of liver transplant rejection (grade 2) and 2 (8.3%) HCT pts had non-serious TEAEs of chronic graft-versus-host disease (grade 1 and 2). No cases of cytokine release syndrome or tumor flare reaction were reported. No AEs were reported as related to tabelecleucel by the treating physician. Conclusions: These updated real-world results for pts with r/r EBV+ PTLD post-HCT or post-SOT treated in the European EAP continue to reinforce the favorable risk:benefit profile of tabelecleucel and are in line with clinical study data supporting its recent EMA approval. [Table: see text]

Metronomic capecitabine inhibits liver transplant rejection in rats by triggering recipients’ T cell ferroptosis

Capecitabine (CAP) is a classic antimetabolic drug and has shown potential antirejection effects after liver transplantation (LT) in clinical studies. Our previous study showed that metronomic CAP can cause the programmed death of T cells by inducing oxidative stress in healthy mice. Ferroptosis, a newly defined non-apoptotic cell death that occurs in response to iron overload and lethal levels of lipid peroxidation, is an important mechanism by which CAP induces cell death. Therefore, ferroptosis may also play an important role in CAP-induced T cell death and play an immunosuppressive role in acute rejection after trans-plantation.To investigate the functions and underlying mechanisms of antirejection effects of metronomic CAP.A rat LT model of acute rejection was established, and the effect of metronomic CAP on splenic hematopoietic function and acute graft rejection was evaluated 7 d after LT. In vitro, primary CD3+ T cells were sorted from rat spleens and human peripheral blood, and co-cultured with or without 5-fluorouracil (5-FU) (active agent of CAP). The levels of ferroptosis-related proteins, ferrous ion concentration, and oxidative stress-related indicators were observed. The changes in mito-chondrial structure were observed using electron microscopy.With no significant myelotoxicity, metronomic CAP alleviated graft injury (Banff score 9 vs 7.333, P < 0.001), prolonged the survival time of the recipient rats (11.5 d vs 16 d, P < 0.01), and reduced the infiltration rate of CD3+ T cells in peripheral blood (6.859 vs 3.735, P < 0.001), liver graft (7.459 vs 3.432, P < 0.001), and spleen (26.92 vs 12.9, P < 0.001), thereby inhibiting acute rejection after LT. In vitro, 5-FU, an end product of CAP metabolism, induced the degradation of the ferritin heavy chain by upregulating nuclear receptor coactivator 4, which caused the accumulation of ferrous ions. It also inhibited nuclear erythroid 2 p45-related factor 2, heme oxygenase-1, and glutathione peroxidase 4, eventually leading to oxidative damage and ferroptosis of T cells.Metronomic CAP can suppress acute allograft rejection in rats by triggering CD3+ T cell ferroptosis, which makes it an effective immunosuppressive agent after LT.

Safety and Efficacy of Conversion to Once-Daily Tacrolimus from Twice-Daily Tacrolimus in Pediatric Liver Transplant Recipients

BackgroundNonadherence to immunosuppression is the most common cause of late acute rejection in pediatric liver transplant (LT) recipients. A prolonged-release once-daily tacrolimus formulation was developed to improve adherence and long-term allograft survival. MethodsWe screened 179 pediatric LT recipients who converted from twice-daily tacrolimus (TD-TAC) to once-daily tacrolimus (OD-TAC) between February 2011 and September 2019. ResultsOne hundred seventy-nine recipients converted to OD-TAC and were followed for 18 months. 152 OD-TAC-converted recipients (84.9%) experienced uneventful follow-up, while 21 recipients showed LFT elevation. Four recipients had biopsy-proven acute rejection within six months of conversion, all of which were successfully treated with steroid pulse. 166 recipients (92.7%) remain on OD-TAC and 13 (7.3%) were switched back to TD-TAC. The mean tacrolimus trough level significantly decreased three months following conversion (3.14 ± 1.9 ng/mL) compared with pre-conversion levels (3.69 ± 1.98 ng/mL). Mean tacrolimus trough levels remained unchanged from 3 months to 12 months following conversion. Percent coefficient of variation of tacrolimus trough levels decreased significantly from 32.5 ± 16.4 ng/mL to 27.5 ± 15.6 ng/mL after conversion to OD-TAC, reflecting a decrease in variation of tacrolimus trough levels following conversion. ConclusionsConversion to OD-TAC in pediatric LT recipients with stable graft function is safe and effective. Level of evidenceLevel IV.

Immature and activated phenotype of blood NK 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 cells samples, spanning from pre-LTx to the first year post-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 CD56brightCD16- subset and a lower cytolytic CD56dimCD16+ in the total blood-circulating NK cells than patients with steady immunity. Both subsets contained a high NKp30 positive population, and CD56dimCD16+ additionally exhibited a high NKp46 positive ratio. The NKp30 positive ratio in CD56dimCD16+ subset showed the most prominent AR predictive ability pre-LTx, and was an independent risk factor of LTx AR. After transplantation, the blood-circulating NK cells in rejectors maintained a higher CD56brightCD16- and lower CD56dimCD16+ composition than the controls throughout the first year post-LTx. Moreover, both subsets maintained a high NKp30 positive ratio, and CD56dimCD16+ 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 CD56brightCD16- 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 CD56dimCD16+ NK subset pre-LTx possessed AR predictive potential.

MiR-27a-5p inhibits acute rejection of liver transplantation in rats by inducing M2 polarization of Kupffer cells through the PI3K/Akt pathway

Liver transplantation (LT), a major therapy for end-stage liver disease, is often associated with acute rejection (AR). MicroRNAs (miRNAs) have been implicated in AR-related gene regulation. In this experiment, the mechanism of miR-27a-5p in AR of LT was studied. Allotransplantation model (LEW-BN) and syngeneic transplantation model (LEW-LEW) of rat orthotopic liver transplantation (OLT) were established. miR-27a-5p was overexpressed in recipient rats 28 days before LT to detect its effects on LT pathology, liver function, and survival time. Kupffer cells (KCs) were isolated and treated with lipopolysaccharide (LPS) and miR-27a-5p overexpression. miR-27a-5p overexpression reduced lymphocyte numbers around portal areas and central veins after LT and mitigated degeneration of epithelial cells of the bile duct. Expression levels of IL-10 and TGF-β1 were increased while IL-12 was decreased. Liver function damage was alleviated and the survival time of rats with LT was prolonged. miR-27a-5p induced M2 polarization of rats with AR after LT and LPS-treated KCs in vitro and promoted activation of the PI3K/Akt pathway in KCs. Inhibition of the PI3K/Akt pathway averted induction of miR-27a-5p on M2 polarization of KCs. Taken together, miR-27a-5p inhibited AR after LT in rats by inducing M2 polarization of KCs through the PI3K/Akt pathway.

Banff 2016 Global Assessment and Quantitative Scoring for T Cell-Mediated Liver Transplant Rejection are Interchangeable.

Histopathological assessment of liver biopsies is the current "gold standard" for diagnosing graft dysfunction after liver transplantation (LT), as graft dysfunction can have nonspecific clinical presentations and inconsistent patterns of liver biochemical dysfunction. Most commonly, post-LT, graft dysfunction within the first year, is due to acute T-cell mediated rejection (TCMR) which is characterised histologically by the degree of portal inflammation (PI), bile duct damage (BDD), and venous endothelial inflammation (VEI). This study aimed to establish the relationship between global assessment, which is the global grading of rejection using a "gestalt" approach, and the rejection activity index (RAI) of each component of TCMR as described in revised Banff 2016 guidelines. Liver biopsies (n = 90) taken from patients who underwent LT in 2015 and 2016 at the Australian National Liver Transplant Unit were identified from the electronic medical records. All biopsy slides were microscopically graded by at least two assessors independently using the revised 2016 Banff criteria. Data were analysed using IBM SPSS v21. A Fisher-Freeman-Halton test was performed to assess the correlation between the global assessment and the RAI scores for each TCMR biopsy. Within the cohort, 60 (37%, n = 164) patients underwent at least 1 biopsy within 12 months after LT. The most common biopsy outcome (total n = 90) was acute TCMR (64, 71.1%). Global assessment of TCMR slides strongly positively correlated with PI (p value <0.001), BDD (p value <0.001), VEI (p value <0.001), and total RAI (p value <0.001). Liver biochemistry of patients with TCMR significantly improved within 4 to 6 weeks post-biopsy compared to the day of the biopsy. In acute TCMR, global assessment and total RAI are strongly correlated and can be used interchangeably to describe the severity of TCMR.

Patients with hepatocellular carcinoma that die during the first year of liver transplantation have high blood sFasL concentrations.

Fas ligand (FasL) is one ligand that activates extrinsic apoptosis pathway. High expression in lymphocytes of FasL have been found in patients with acute rejection of liver transplantation (LT). No high blood concentrations of soluble FasL (sFasL) have been found in patients with acute LT rejection; however, the samples size of those studies was small. To determine whether patients with hepatocellular carcinoma (HCC) that dead during the first year of LT have higher blood sFasL concentrations previously to LT that those who that remain alive in a study of higher sample size. Patients underwent LT due to HCC were included in this retrospective study. Serum sFasL levels prior to LT were measured and one-year LT mortality was registered. Non-surviving patients (n = 14) showed higher serum sFasL levels [477 (269-496) vs 85 (44-382) pg/mL; P < 0.001] than surviving patients (n = 113). Serum sFasL levels (pg/mL) were associated with mortality (OR = 1.006; 95%CI = 1.003-1.010; P = 0.001) independently of age of LT donor in the logistic regression analysis. We report for the first time that HCC patients who die within the first year of HT have higher blood sFasL concentrations prior to HT than those who remain alive.

A254 HEPATIC SEQUELAE OF POST-ACUTE COVID-19 SYNDROME (PACS): A SYSTEMATIC REVIEW OF THE CURRENT LITERATURE

Abstract Background Post-acute COVID-19 syndrome (PACS), colloquially known as long-COVID, is a syndrome characterized by persistent or delayed symptoms four weeks or beyond from initial infection onset. Observational studies have shown liver injury during acute COVID-19 infection, particularly in severe infections requiring hospitalization. This has been observed in forms of increased liver enzyme markers, imaging, fibrosis and transplant rejection. However, the data on resolution of abnormal liver injury markers is inconsistent. As such, the long-term hepatic sequelae following acute COVID-19 infection remains unclear. Purpose To assess the current understanding of long-term hepatic sequalae of COVID-19 in adults, and to identify prevalence and odds of liver complications in patients with PACS compared to COVID-negative individuals. Method Included criteria consisted of observational or cross-sectional studies with patients ≥18y at least four weeks following COVID-19 infection evaluating liver disease/involvement. Liver involvement was defined as per primary study, in order to accomodate various modalities of hepatic injury (e.g. lab markers, imaging, etc.). Case reports or series, systematic reviews, literature reviews, meta-analyses, editorials and commentaries were excluded, as well as studies that report liver function/injury only during acute COVID-19 infection rather than following. Systematic searches were performed on MEDLINE, CINAHL and EMBASE. All studies were screened by two independent reviewers. Risk of bias was assessed by two independent reviewers using the Cochrane ROBIN-E tool. All conflicts from screening, data extraction and risk of bias assessment stages were resolved by a third independent reviewer. Data on biochemical liver markers, imaging, fibrosis and clinical scores were collected where available. Result(s) 2734 studies were found and 614 duplicates were removed. 2117 abstracts and 35 subsequent full texts were screened. Most studies were high or very high risk of bias; only two studies were found to be low risk of bias. Only nine studies utilized control groups. Most studies assessed liver enzymes. 22 of 26 studies suggested some type of abnormality in hepatic testing following COVID-19 infection. 14 studies suggested persistently abnormal liver function tests in PACS patients. 5 studies suggested persistent imaging, fibrosis or autopsy abnormalities. Given the high risk of bias, meta-analysis could not be reliably performed among all included studies. Conclusion(s) Despite most studies suggesting there is a proportion of patients who suffer from prolonged liver abnormalities such as elevated liver enzymes or fibrosis on imaging, the reliability of these fundings is uncertain given high risk of bias and lack of consistent control groups. As such, there is insufficient high-quality data to inform the natural history of hepatic sequalae following COVID-19 infection. Further high-quality research is required in this field to inform future clinical decisions. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Risk factors for antibody-mediated rejection in ABO blood-type incompatible and donor-specific antibody-positive liver transplantation.

Antibody-mediated rejection (AMR) is a refractory rejection after ABO blood-type incompatible (ABOi) or donor-specific antibody (DSA)-positive liver transplantation (LT). Pretransplant rituximab desensitization dramatically reduced posttransplant AMR development; however, risk factors for AMR in the rituximab era remain unclear in both ABOi living-donor LT (ABOi-LDLT) and preformed DSA-positive LT (pDSA-LT). Of our 596 adult LDLTs (≥18y) after rituximab introduction (2004-2019), 136 were ABOi-LDLT (22.8%). After excluding retransplants (9), acute liver failure (7), and protocol deviations (16), 104 ABOi-LDLTs were finally enrolled. Of these, 19 recipients developed AMR, 18 of which occurred within 2 weeks after transplantation (95%). ABOi-AMR significantly worsened graft and recipient survival than those without ( p =0.02 and 0.04, respectively). Model for End-stage Liver Disease (MELD) ≤13 (OR: 5.15 [1.63-16.3], p =0.005) and pre-rituximab anti-ABO IgM-titer ≥128 (OR: 3.25 [1.05-10.0], p =0.03) were identified as independent risk factors for ABOi-AMR development. Recipients fulfilling both factors showed significantly worse survival rates than those who did not ( p =0.003). Of 352 adult LTs, after introducing the LABScreen Single Ag method (2009-2019), pDSA with mean fluorescence intensity (MFI) ≥500 was detected in 50 cases (14.2%). After excluding 10 ABOi-LDLTs, 40 pDSA-LTs were finally analyzed, of which 5 developed AMR. The combination of high-titer (sum-MFI ≥10,000) and multi-loci pDSAs was a significant risk factor for pDSA-AMR development ( p <0.001); however, it did not affect the 5-year recipient survival compared with those without ( p =0.56). In conclusion, preoperative MELD ≤13 and pre-rituximab anti-ABO IgM-titer ≥128 for ABOi-LDLT, and the combination of sum-MFI ≥10,000 and multi-loci pDSAs for pDSA-LT, are risk factors for AMR in the era of rituximab desensitization. Characteristically, ABOi-AMR significantly deteriorated graft and recipient survival, whereas pDSA-AMR did not.

Human leukocyte antigen antibodies and leukocyte antigen/killer-cell immunoglobulin-like receptor genes are important in transplant immunology in the liver

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.

Dendritic cells originating exosomal miR-193b-3p induces regulatory T cells to alleviate liver transplant rejection

Exosomes exert considerable influence in mediating regulatory T (Treg) cells differentiation, which attach great importance to attenuating acute cellular rejection after liver transplantation (LT). And, miRNAs are known to play essential roles in cell-cell communication delivered by exosomes. However, the function of exosomal miRNAs in regulating Treg cells after LT remains unknown. Here, we performed an expression profiling analysis of exosome-miRNAs from human plasma after LT and investigated their immunoregulatory effects on Treg cells. Fifty-eight LT patients and nine donors were included in this report. miRNA profiles in plasma exosomes were analyzed using next-generation sequencing. Flow cytometry, HE and multiplex immunofluorescent staining were used to identify Treg cells in the liver and peripheral blood. A lentiviral vector system was used to overexpress miR-193b-3p in dendritic cells (DCs), and exosomes isolated from these transfected cells were co-cultured with spleen lymphocytesin vitro. A quantitative Real-time PCR and enzyme-linked immunosorbent assay were used to detect the expression of cytokines. Treg cell infiltration was increased in the liver along with Th17 and CD8+ T cell, and it was down-regulated in peripheral blood in the acute rejection group. High-throughput sequencing revealed that miR-193b-3p was markedly up-regulated in plasma exosomes of non-rejection LT patients. The NLRP3 inflammasome was screened as a target for miR-193b-3p based on target prediction and functional enrichment analyses. Exosomal miR-193b-3p derived from DCs increased Treg cells as demonstrated in vitro. miR-193b-3p overexpression down-regulated NLRP3 as well as the inflammatory cytokines IL-1β and IL-17A while increasing levels of the cytokines IL-10 and TGF-β. DC derived exosomal miR-193b-3p promoted Treg cells by inhibiting NLRP3 expression. These findings not only provide a new perspective on the mechanisms, but also hold great promise for the treatment or prevention of liver allograft rejection.

Risk factors for acute rejection in liver transplantation and its impact on the outcomes of recipients

ObjectiveTo determine the risk factors for acute rejection in liver transplantation and its impact on the outcomes of the recipients. MethodsClinicopathological data of 290 patients who underwent liver transplantation from January 2012 to December 2021 at our center were retrospectively evaluated. Patients were grouped into an acute rejection (AR) group and a normal (NM) group based on the confirmed histopathological diagnosis of acute rejection. Univariate and multivariate logistic regression were used to determine the risk factors for acute rejection. Results244 patients were included in the study. Acute rejection occurred in 27 (11.1%) of the patients. Warm ischemia time (P = 0.137), cold ischemia time (P = 0.064) and chronic liver failure (P = 0.001) were potential risk factors for acute rejection. Chronic liver failure (P < 0.001, OR = 8.22, 95% CI = 2.47–27.32) was the independent risk factor. There was no significant difference in overall survival between recipients with acute rejection and those without it (P = 0.985). The 1-, 3- and 5-year overall survival in the NM group was 98.1%, 85.7% and 78.6% respectively vs 88.9%, 82.5% and 82.5% respectively in the AR group. ConclusionAcute rejection does not appear to affect the long-term survival of the recipients. Only chronic liver failure was an independent risk factor for acute rejection. Our findings further illustrate that contradictions still exist on which factors influence acute rejection in liver transplant recipients. SummaryClinicopathological data of 290 liver transplant recipients at our center between January 2012 and December 2021 were retrospectively evaluated to determine the risk factors for acute rejection and its impact on the outcomes of the recipients. 244 patients were included in the analysis. 27 of the 244 experienced acute rejection. Propensity score matching was performed to reduce the confounding effect. Patients were assigned to an acute rejection group (n = 27) and a normal group (n = 54). Chronic liver failure (P < 0.001, OR = 8.22, 95% CI = 2.47–27.32) was the determined to be independent risk factor for acute rejection. Acute rejection did not appear to affect the long-term survival of the recipients and there was no significant difference in overall survival between the patients with acute rejection and those without it.

Investigation of the Association Between the ITPA Gene 94C>A Gene Sequence Variant and Liver Transplant Rejection in Iranian Liver Transplant Recipients.

Inosine triphosphate pyrophosphatase is an enzyme encoded by the ITPA gene and functions to prevent the incorporation of thiopurine nucleotides into DNA and RNA. Thiopurine drug metabolites such as azathioprine and 6-mercaptopurine have been included in the lists of inosine triphosphate pyrophosphatase substrates. Inosine triphosphatase gene alterations are other pharmacogenetic sequence variants possibly involved in thiopurine metabolism. This study aimed to evaluate the possible association between ITPA 94C>A gene sequence variant (C-to-A substitution at nucleotide 94) in liver transplant recipients. The genotyping of ITPA 94C>A was evaluated by the polymerase chain reaction- restriction fragment length polymorphism method in 200 liver transplant recipients as well as 100 controls. Data were analyzed with SPSS statistical software. This study showed statistically significant associations between the CA genotype of the ITPA 94C>A sequence variant and liver transplant in the rejection and nonrejection groups. Moreover, the results reported in this study showed no significant differences between sex, age, and blood group in patients with liver transplant (with or without transplant rejection). Our results indicated that there were statistically significant associations of the CA genotype of ITPA 94C>A sequence variant with liver transplant in the rejection and nonrejection groups. Further studies are recommended.

Comparative analysis and trends in liver transplant hospitalizations with Clostridium difficile infections: A 10-year national cross-sectional study.

Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhea in the United States. We aimed to determine comparative trends in inpatient outcomes of liver transplant (LT) patients based on CDI during hospitalizations. The national inpatient sample database was used to conduct the present retrospective study regarding CDI among the LT hospitalizations from 2009 to 2019. Primary outcomes included 10-year comparative trends of the length of stay (LOS) and mean inpatient charges (MIC). Secondary outcomes included comparative mortality and LT rejection trends. There was a 14.05% decrease in CDI in LT hospitalizations over the study period (p=.05). The trend in LOS did not significantly vary (p=.9). MIC increased significantly over the last decade in LT hospitalizations with CDI (p<.001). LT hospitalizations of autoimmune etiology compared against non-autoimmune did not increase association with CDI, adjusted odds ratio (aOR) 0.97 (95% confidence interval [CI] 0.75-1.26, p=.87). CDI was associated with increased mortality in LT hospitalizations, aOR 1.84 (95% CI 1.52-2.24, p<.001). In-hospital mortality for LT hospitalizations with CDI decreased by 7.75% over the study period (p=.3). CDI increased transplant rejections, aOR 1.3 (95% CI 1.08-1.65, p<.001). There was a declining trend in transplant rejection for LT hospitalization with CDI from 5% to 3% over the study period (p=.0048). CDI prevalence does not increase based on autoimmune LT etiology. It increases mortality in LT hospitalizations; however, trend for mortality and transplant rejections has been declining over the last decade.

Metabolomics profiling in acute liver transplant rejection in a pediatric population

Pediatric liver transplantation rejection affects 20% of children. Currently, liver biopsy, expensive and invasive, is the best method of diagnosis. Discovery and validation of clinical biomarkers from blood or other biospecimens would improve clinical care. For this study, stored plasma samples were utilized from two cross-sectional cohorts of liver transplant patients at Children’s Healthcare of Atlanta. High resolution metabolic profiling was completed using established methods. Children with (n = 18) or without (n = 25) acute cellular rejection were included in the analysis (n = 43 total). The mean age of these racially diverse cohorts ranged from 12.6 years in the rejection group and 13.6 years in the no rejection group. Linear regression provided 510 significantly differentiating metabolites between groups, and OPLS-DA showed 145 metabolites with VIP > 2. A total of 95 overlapping significant metabolites between OPLS-DA and linear regression analyses were detected. Pathway analysis (p < 0.05) showed bile acid biosynthesis and tryptophan metabolism as the top two differentiating pathways. Network analysis also identified tryptophan and clustered with liver enzymes and steroid use. We conclude metabolic profiling of plasma from children with acute liver transplant rejection demonstrates > 500 significant metabolites. This result suggests that development of a non-invasive biomarker-based test is possible for rejection screening.