What is the long-term outcome of the liver allograft?

GraftIQ: Hybrid multi-class neural network integrating clinical insight for multi-outcome prediction in liver transplant recipients

Liver transplant recipients (LTRs) are at risk of graft injury, leading to cirrhosis and reduced survival. Liver biopsy, the diagnostic gold standard, is invasive and risky. We developed a hybrid multi-class neural network (NN) model, 'GraftIQ,' integrating clinician expertise for non-invasive graft pathology diagnosis. Biopsies from LTRs (1992-2020) were classified into six categories using demographic, clinical, and lab data from 30 days pre-biopsy. The dataset (5217 biopsies) was split 70/30 for training/testing, with external validation at Mayo Clinic, Hannover Medical School, and NUHS Singapore. Bayesian fusion was used to combine clinician-derived probabilities with NN predictions, improving performance. Here we show that GraftIQ (MulticlassNN+clinical insight) achieved an AUC of 0.902 (95% CI:0.884-0.919), up from 0.885 with NN alone. Internal and external validation demonstrated 10-16% higher AUC than conventional ML models. GraftIQ demonstrates high accuracy in identifying graft etiologies and offers a valuable clinical decision support tool for LTRs.

Utilizing Machine Learning to Predict Liver Allograft Fibrosis by Leveraging Clinical and Imaging Data

BACKGROUND AND AIM

Liver transplant (LT) recipients may succumb to graft-related pathologies, contributing to graft fibrosis (GF). Current methods to diagnose GF are limited, ranging from procedural-related complications to low accuracy. With recent advances in machine learning (ML), we aimed to develop a noninvasive tool using demographic, clinical, laboratory, and B-mode ultrasound (US) features to predict significant fibrosis (METAVIR≥F2).

METHODS

We used a nested 10-fold cross-validation approach with grid-search for hyperparameter fine-tuning to train an artificial neural network (ANN) and a support vector machine (SVM) to classify mild fibrosis (F0-F1) and significant fibrosis (F2-F4) on 1131 patients. We calculated Shapley values to identify top-ranked features, determining the contribution of each feature to model predictions. For the imaging-based model, we used 4819 images with 892 studies trained on the residual network 18 (ResNet18) model to classify F0-F1 versus F3-F4.

RESULTS

We determined the ANN performed the best when compared to the SVM and standard biomarkers, with an AUC ranging from 0.77 to 0.81. The ResNet18 model was unable to diagnose advanced GF, leading to the training AUCs ranging from 0.89 to 0.97, while the validation and testing AUCs were 0.43-0.63. Shapley analysis highlighted the following top-ranked features associated with significant GF: hepatitis C at transplant, recipient age, recipient sex, and certain blood markers such as creatinine and hemoglobin.

CONCLUSION

Noninvasive approaches using ML for predicting significant GF perform well when considering demographic, clinical, and laboratory data; however, this performance is not enhanced with the use of US images.

A critical review of microbiome-derived metabolic functions and translational research in liver diseases

Significant changes in gut microbial composition are associated with chronic liver disease. Using preclinical models, it has been demonstrated that ethanol/alcohol-induced liver disease is transmissible through fecal microbiota transplantation (FMT). So, the survival rate of people with severe alcoholic hepatitis got better, which suggests that changes in the makeup and function of gut microbiota play a role in metabolic liver disease. The leaky intestinal barrier plays a major role in influencing metabolic-related liver disease development through the gut microbiota. As a result, viable bacteria and microbial products can be transported to the liver, causing inflammation, contributing to hepatocyte death, and causing the fibrotic response. As metabolic-related liver disease starts and gets worse, gut dysbiosis is linked to changes in the immune system, the bile acid composition, and the metabolic function of the microbiota in the gut. Metabolic-related liver disease, as well as its self-perpetuation, will be demonstrated using data from preclinical and human studies. Further, we summarize how untargeted treatment approaches affect the gut microbiota in metabolic-related liver disease, including dietary changes, probiotics, antibiotics, and FMT. It discusses how targeted therapies can improve liver disease in various areas. These approaches may improve metabolic-related liver disease treatment options.

Protocol liver biopsy predicts graft survival after liver transplantation

BACKGROUND

The use of protocol liver biopsy to monitor liver allograft status remains controversial. There is limited data from modern transplantation populations that includes protocol biopsies to evaluate its value in predicting clinical outcomes.

METHODS

All protocol liver biopsies were identified from 875 patients who underwent liver transplantation at Helsinki University Hospital between 2000 and 2019. Each histologic component was analyzed for its ability to predict long-term outcomes, especially graft survival. We determined the frequency of significant biopsy findings based on the Banff working group definition. Liver function tests (LFTs) and clinical markers were evaluated for their ability to predict significant biopsy findings.

RESULTS

In total, 867 protocol liver biopsies were analyzed. Significant findings were identified in 20.1% of the biopsies. In the first protocol biopsy, steatohepatitis (hazard ratio [HR] 3.504, p = .03) and moderate or severe congestion (HR 3.338, p = .04) predicted graft loss. The presence of cholangitis (HR 2.563, p = .04), necrosis (HR 7.635, p < .001), mild congestion (HR 4.291, p = .009), and significant biopsy finding (HR 2.540, p = .02) predicted inferior death-censored graft survival. While the degree of elevation of LFTs was positively associated with significant biopsy findings, the discrimination was poor (AUC .572-.622). Combined LFTs and clinical risk factors remained suboptimal for discriminating significant biopsy findings (AUC .696).

CONCLUSIONS

Our findings support the use of protocol liver biopsies after liver transplantation since they frequently revealed changes associated with long-term outcomes, even when LFTs were normal.

Long-term Outcome of Asymptomatic Patients With Graft Fibrosis in Protocol Biopsies After Pediatric Liver Transplantation

BACKGROUND

The histological prevalence of allograft fibrosis in asymptomatic children after liver transplantation (LT) is well documented. However, long-term graft and patient survival remain unclear. This retrospective multicenter study aims to determine the prevalence of allograft fibrosis and analyze the long-term outcome for patients transplanted in childhood.

METHODS

We reviewed clinical data of children who had undergone 10-y protocol liver biopsies. We excluded patients with autoimmune hepatitis, primary sclerosing cholangitis, hepatitis B or C, and retransplantation. In total, 494 patients transplanted in childhood across 12 international transplant centers were included. We evaluated the development of fibrosis by comparing the results with biopsies obtained 5 and 15 y post-LT. Histological findings were correlated with graft and patient survival up to 20 y post-LT.

RESULTS

In the 10-y biopsies, periportal or pericentral fibrosis was observed in 253 patients (51%), 87 (18%) had bridging fibrosis, 30 (6%) had cirrhosis, and 124 (25%) had no fibrosis. The prevalence and stage of graft fibrosis significantly progressed from 5 to 10 y. At 10 y, the severity of fibrosis correlated significantly with inflammation. Patients with graft cirrhosis in the 10-y biopsy were more likely to die or require retransplantation subsequently ( P = 0.027).

CONCLUSIONS

At 10 y post-LT, most patients transplanted in childhood developed fibrosis, based on the protocol liver biopsies. Although mild-to-moderate graft fibrosis did not largely affect patient or graft survival up to 20 y post-LT, this progressive fibrosis finding has substantial implications for developing cirrhosis and portal hypertension in adult care.

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

Fibrosis and steatosis of the liver graft: Are non-invasive tests useful? A short review

As life expectancy of liver transplanted patients improves, new questions are arising to avoid progressive graft loss. The spectrum of chronic inflammation and fibrosis are known to be important triggers in the alteration of graft function. Liver biopsy remains the gold standard to better understand progressive, normal, and abnormal histological modifications of the graft. In parallel, the interest for metabolic steatosis development in post-transplantation is also growing. Long-term survival of these patients involves the management of comorbidities including metabolic syndrome and cardiovascular diseases. Early detection of altered graft parenchyma, and monitoring of its evolution are undoubtedly essential. Non-invasive methods including transient elastography and fibrosis biomarkers are attractive tools to avoid drawbacks and complications of liver biopsy. Accuracy of these methods are well-known in a pre-transplantation setting, but evidence is lacking in post-transplantation setting. We review current knowledge of progressive liver fibrosis and steatosis development after transplantation and non-invasive methods of their assessment.

Evidence for Alloimmune Sinusoidal Injury in De Novo Nodular Regenerative Hyperplasia After Liver Transplantation

Posttransplant nodular regenerative hyperplasia (NRH) mostly remains unexplained. Microvascular injury due to antibody-mediated rejection (AMR) is suspected, but lack of donor specific antibody (DSA) testing makes it difficult to prove. Centered around a 1-year period of routine DSA testing, concomitant protocol, and indicated posttransplant liver biopsies (LB), recipients with NRH (n = 18) were compared with a matched control group (n = 36). All index, previous, and subsequent LB were reviewed. Both groups were similar in terms of demographics, timing of index LB, and DSA. In the index LB, the NRH group had higher sinusoidal C4d positivity (p = 0.029) and perisinusoidal fibrosis (p = 0.034), both independently associated with NRH (p = 0.038 and 0.050, respectively). Features of "possible" chronic AMR were detected in 28.5% of the NRH group without a known cause and 0% of the control group (p = 0.009). The NRH group had more preceding indicated LB with increased incidence of rejection and biliary obstruction pattern. In the follow-up histology, overall, sinusoidal and portal C4d positivity, sinusoidal microvasculitis, and perisinusoidal fibrosis were also higher (all p < 0.050). In conclusion, we provide evidence towards the hypothesis that some cases of posttransplant NRH are related to preceding active and persistent AMR. Large multicenter studies with protocol DSA testing are required to confirm.

The role of immunosuppression in long-term graft hepatitis and fibrosis after paediatric liver transplant - comparison of two treatment protocols

Background and aims

We have previously demonstrated high rates of chronic allograft hepatitis and fibrosis in liver transplant patients on long-term cyclosporine monotherapy. We subsequently changed practice to add low-dose prednisolone to maintenance treatment with tacrolimus post-transplant. The aim of the study was to assess the impact of the immunosuppression change on graft histopathology.

Methods

Patients treated in this era (Tac + Pred, 2000-2009, N = 128) were compared to a historical cohort, who had been maintained on a steroid-free, cyclosporine-based regime (CSA-Only, 1985-1996, N = 129). Protocol liver biopsies and laboratory tests were performed five- and ten-years post-transplant in both groups.

Results

Compared to CSA-Only, the Tac + Pred cohort had significantly lower rates of chronic hepatitis (CH) at five (20% vs. 44%, p < 0.001) and ten (15% vs. 67%, p < 0.001) years post-transplant, with similar trends observed in inflammation and fibrosis at five years. The Tac + Pred cohort also had significantly lower hepatic transaminases and IgG levels and was less likely to be autoantibody positive at both time points. However, the degree of graft fibrosis at ten years did not differ significantly between eras (p = 0.356).

Conclusion

Increased immunosuppression effectively reduced chronic allograft hepatitis and fibrosis at five years, suggesting it is an immunologically driven variant of rejection. However, there was no significant reduction in the degree of fibrosis at ten years, indicating a multifactorial origin for long term graft fibrosis.

Research Progress of Fecal Microbiota Transplantation in Liver Diseases

A growing body of evidence suggested that gut microbiota is associated with liver diseases through the gut-liver axis. The imbalance of gut microbiota could be correlated with the occurrence, development, and prognosis of a series of liver diseases, including alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), viral hepatitis, cirrhosis, primary sclerosing cholangitis (PSC), and hepatocellular carcinoma (HCC). Fecal microbiota transplantation (FMT) seems to be a method to normalize the patient's gut microbiota. This method has been traced back to the 4th century. In recent decade, FMT has been highly regarded in several clinical trials. As a novel approach to reconstruct the intestinal microecological balance, FMT has been used to treat the chronic liver diseases. Therefore, in this review, the role of FMT in the treatment of liver diseases was summarized. In addition, the relationship between gut and liver was explored through the gut-liver axis, and the definition, objectives, advantages, and procedures of FMT were described. Finally, the clinical value of FMT therapy in liver transplant (LT) recipients was briefly discussed.

Long-term Clinical Outcomes and Predictive Factors for Living-donor Liver Transplant Recipients With Biliary Strictures

BACKGROUND

Biliary strictures frequently occur in living-donor liver transplant (LDLT) recipients. However, long-term clinical outcomes and their associated factors are unclear.

METHODS

We analyzed an historical cohort of 228 recipients who underwent LDLT with post-liver transplantation biliary strictures. Endoscopic retrograde cholangiography or percutaneous transhepatic biliary drainage were performed to treat biliary strictures. Patients that experienced persistent jaundice over 3 mo after the initial treatment were defined as a remission-failure group.

RESULTS

Median observation period was 8.5 y after the diagnosis of biliary stricture. The 15-y graft survival (GS) rate was 70.6%, and 15-y rate of developing portal hypertension (PH) was 26.1%. Remission failure occurred in 25.0% of study participants. In the multivariate analysis, biopsy-proven acute rejection, and portal vein/hepatic artery abnormalities were risk factors for remission failure. Development of PH, retransplantation, and death were significantly more frequent in the remission-failure group. Remission failure and PH were associated with poor GS. In multivariate analyses, hepatic artery abnormality and biloma were common significant factors that were associated with a poor GS and development of PH.

CONCLUSIONS

The insufficient blood supply reflected by hepatic artery abnormality and biloma might be the most important factor that can predict poor long-term survival in LDLT patients with biliary strictures. Future large-scale prospective studies are needed to validate our observations.

Standardizing the histological assessment of late posttransplantation biopsies from pediatric liver allograft recipients

Excellent short-term survival after pediatric liver transplantation (LT) has shifted attention toward the optimization of long-term outcomes. Despite considerable progress in imaging and other noninvasive modalities, liver biopsies continue to be required to monitor allograft health and to titrate immunosuppression. However, a standardized approach to the detailed assessment of long-term graft histology is currently lacking. The aim of this study was to formulate a list of histopathological features relevant for the assessment of long-surviving liver allograft health and to develop an approach for assessing the presence and severity of these features in a standardized manner. Whole-slide digital images from 31 biopsies obtained ≥4 years after transplantation to determine eligibility for an immunosuppression withdrawal trial were selected to illustrate a range of typical histopathological findings seen in children with clinically stable grafts, including those associated with alloantibodies. Fifty histological features were independently assessed and, where appropriate, scored semiquantitatively by six pathologists to determine inter- and intraobserver reproducibility of the histopathological features using unweighted and weighted kappa statistics; the latter metric enabled distinction between minor and major disagreements in parameter severity scoring. Weighted interobserver kappa statistics showed a high level of agreement for various parameters of inflammation, interface activity, fibrosis, and microvascular injury. Intraobserver agreement for these features was even more substantial. The results of this study will help to standardize the assessment of biopsies from long-surviving liver allografts, aid the recognition of important histological features, and facilitate international comparisons and clinical trials aiming to improve outcomes for children undergoing LT.

Long-term liver allograft fibrosis: A review with emphasis on idiopathic post-transplant hepatitis and chronic antibody mediated rejection

Liver transplantation (LT) is a life-saving surgical procedure and the current standard of care for most patients with end stage liver disease. With improvements in organ preservation techniques, perioperative care, and immunosuppression, there is better patient and graft survival following LT, and assessment of the liver allograft in long-term survivors is becoming increasingly important. Recurrent or de novo viral or autoimmune injury remains the most common causes of chronic hepatitis and fibrosis following liver transplantation in adults. However, no obvious cause can be identified in many adults with controlled recurrent disease and the majority of pediatric LT recipients, as they have been transplanted for non-recurrent liver diseases. Serial surveillance liver biopsies post LT have been evaluated in several adult and pediatric centers to identify long-term pathological changes. Pathological findings are frequently present in liver biopsies obtained after a year post LT. The significance of these findings is uncertain as many of these are seen in protocol liver biopsies from patients with clinically good allograft function and normal liver chemistry parameters. This narrative review summaries the factors predisposing to long-term liver allograft fibrosis, highlighting the putative role of idiopathic post-LT hepatitis and chronic antibody mediated rejection in its pathogenesis.

Value of posttransplant protocol biopsies in 2 biliary autoimmune liver diseases: A step toward personalized immunosuppressive treatment

The value of protocol liver graft biopsies with good liver function was evaluated in patients with primary sclerosing cholangitis (PSC) or primary biliary cholangitis (PBC).A total of 250 protocol liver biopsy reports from 182 PSC and PBC patients were compared. Overall histopathological findings and those leading to changes in immunosuppression therapy were retrospectively analyzed.The mean time to first protocol biopsy after transplantation was 5.5 (±4.5) years for PSC patients and 9.3 (±6.6) years for PBC patients. More than 1 abnormal histopathological parameter was found in 43% and 62% of PSC and PBC patients, respectively. However, the histology was interpreted as normal by the pathologist in 78% of PSC and 60% of PBC patients. Immunosuppression therapy was reduced in 10% and increased in 6% patients due to protocol biopsy findings. Biopsies leading to increased immunosuppression therapy had more portal (P = .004), endothelial (P = .008), interphase (P = .021), and lobular (P = .000) inflammation.Mild histopathological findings were frequently found in the protocol biopsies despite the normal biochemistry. PBC patients had more histological abnormalities than those transplanted due to PSC; however, PBC patients had longer follow-up times. Immunosuppression therapy could be safely increased or decreased according to protocol biopsy findings after multidisciplinary meeting discussions.

Evaluation of Graft Fibrosis, Inflammation and Donor-specific Antibodies at Protocol Liver Biopsies in Pediatric Liver Transplant Patients: a Single Center Experience

BACKGROUND

The impact of graft fibrosis and inflammation on the natural history of pediatric liver transplants (LT) is still debated. Our objectives were to evaluate the evolution of posttransplant fibrosis and inflammation over time at protocol liver biopsies (PLBs), risk factors for fibrosis, presence of donor-specific antibodies (DSAs) and/or their correlation with graft and recipient factors.

METHODS

A single-center, retrospective (2000-2019) cross-sectional study on pediatric LT recipients who had at least one PLB, followed by a longitudinal evaluation in those who had at least two PLBs, was conducted. Fibrosis was assessed by the Liver Allograft Fibrosis Semiquantitative score, inflammation by the Rejection Activity Index, DSAs by Luminex®.

RESULTS

A total of 134 PLBs from 94 patients were included. Fibrosis was detected in 87% (30% mild, 45% moderate, 12% severe), 80% in the portal tracts. There was an increase in fibrosis between the 1-3 and the 4-6 year group (p=0.01), then it was stable. Inflammation was observed in 44% (30% mild, 13% moderate, 1% severe), 90% in the portal tracts. Anti-HLA II (IgG) DSAs were detected in 14/40 (35%). Portal fibrosis was associated with portal inflammation in the 1-3 year group (p=0.04). Low immunosuppression levels were correlated with sinusoidal fibrosis (p=0.04) and DSA positivity (p-value=0.006). There was no statistically significant correlation between DSA positivity and the presence of graft fibrosis or inflammation.

CONCLUSIONS

This study corroborates the concept of an early evolution of silent graft fibrosis. Suboptimal immunosuppression may play a role in the development of fibrosis and DSAs.

The Fourth International Workshop on Clinical Transplant Tolerance

The International Workshop on Clinical Transplant Tolerance is a biennial meeting that aims to provide an update on the progress of studies of immunosuppression minimization or withdrawal in solid organ transplantation. The Fourth International Workshop on Clinical Tolerance was held in Pittsburgh, Pennsylvania, September 5-6, 2019. This report is a summary of presentations on the status of clinical trials designed to minimize or withdraw immunosuppressive drugs in kidney, liver, and lung transplantation without subsequent evidence of rejection. All protocols had in common the use of donor or recipient cell therapy combined with organ transplantation. The workshop also included presentations of mechanistic studies designed to improve understanding of the cellular and molecular basis of tolerance and to identify potential predictors/biomarkers of tolerance. Strategies to enhance the safety of hematopoietic cell transplantation and to improve patient selection/risk stratification for clinical trials were also discussed.

DSA Are Associated With More Graft Injury, More Fibrosis, and Upregulation of Rejection-associated Transcripts in Subclinical Rejection

BACKGROUND

Subclinical T cell-mediated rejection (subTCMR) is commonly found after liver transplantation and has a good short-term prognosis, even when it is left untreated. Donor-specific antibodies (DSA) are putatively associated with a worse prognosis for recipient and graft after liver transplantation.

METHODS

To assess the immune regulation in subTCMR grafts, gene expression of 93 transcripts for graft injury, tolerance, and immune regulation was analyzed in 77 biopsies with "no histologic rejection" (NHR; n = 25), "clinical TCMR" (cTMCR; n = 16), and subTCMR (n = 36). In addition, all available subTCMR biopsies (n = 71) were tested for DSA with bead assays.

RESULTS

SubTCMR showed heterogeneous and intermediate expression profiles of transcripts that were upregulated in cTCMR. Graft gene expression suggested a lower activation of effector lymphocytes and a higher activation of regulatory T cells in grafts with subTCMR compared to cTCMR. DSA positivity in subTCMR was associated with histological evidence of more severe graft inflammation and fibrosis. This more severe DSA+ associated graft injury in subTCMR was converged with an upregulation of cTCMR-associated transcripts. In nonsupervised analysis, DSA positive subTCMR mostly clustered together with cTCMR, while DSA negative subTCMR clustered together with NHR.

CONCLUSIONS

T cell-mediated rejection seems to form a continuum of alloimmune activation. Although subTCMR exhibited less expression of TCMR-associated transcript, DSA positivity in subTCMR was associated with an upregulation of rejection-associated transcripts. The identification of DSA positive subclinical rejection might help to define patients with more inflammation in the graft and development of fibrosis.

Non-invasive screening for subclinical liver graft injury in adults via donor-specific anti-HLA antibodies

The majority of liver grafts exhibit abnormal histological findings late after transplantation, even when liver enzymes are normal. Such subclinical graft injuries were associated with rejection and fibrosis progression in recent studies. The identification of non-invasive biomarkers for subclinical graft injury might help to individualize immunosuppression. Therefore, graft injury was assessed in 133 liver biopsies with normal/near normal liver enzymes from a prospective liver biopsy program. Cytokeratin-18 cell death marker (M65) and donor specific anti-HLA antibodies (DSA) were measured as non-invasive markers in paired plasma samples in addition to routine parameters. M65 was associated with subclinical graft injury but this association was too weak for reasonable clinical application. DSA positivity was associated with more graft inflammation (OR = 5.4) and more fibrosis (OR = 4.2). Absence of DSA excluded fibrosis in 87–89%, while presence of DSA excluded histological criteria for immunosuppression minimization attempts in 92–97%. While CK18 cell death marker had no diagnostic value for the detection of subclinical liver graft injury, DSA testing can help to preselect patients for immunosuppression reduction in case of DSA negativity, while DSA positivity should prompt elastography or liver biopsy for the assessment of subclinical graft injury.

Enhancing the Value of Histopathological Assessment of Allograft Biopsy Monitoring

Traditional histopathological allograft biopsy evaluation provides, within hours, diagnoses, prognostic information, and mechanistic insights into disease processes. However, proponents of an array of alternative monitoring platforms, broadly classified as "invasive" or "noninvasive" depending on whether allograft tissue is needed, question the value proposition of tissue histopathology. The authors explore the pros and cons of current analytical methods relative to the value of traditional and illustrate advancements of next-generation histopathological evaluation of tissue biopsies. We describe the continuing value of traditional histopathological tissue assessment and "next-generation pathology (NGP)," broadly defined as staining/labeling techniques coupled with digital imaging and automated image analysis. Noninvasive imaging and fluid (blood and urine) analyses promote low-risk, global organ assessment, and "molecular" data output, respectively; invasive alternatives promote objective, "mechanistic" insights by creating gene lists with variably increased/decreased expression compared with steady state/baseline. Proponents of alternative approaches contrast their preferred methods with traditional histopathology and: (1) fail to cite the main value of traditional and NGP-retention of spatial and inferred temporal context available for innumerable objective analyses and (2) belie an unfamiliarity with the impact of advances in imaging and software-guided analytics on emerging histopathology practices. Illustrative NGP examples demonstrate the value of multidimensional data that preserve tissue-based spatial and temporal contexts. We outline a path forward for clinical NGP implementation where "software-assisted sign-out" will enable pathologists to conduct objective analyses that can be incorporated into their final reports and improve patient care.

Role of Autoimmunity in Patients Transplanted for Acute Liver Failure of Unknown Origin: A Clinical and Graft Biopsy Analysis

The etiology and prognosis of acute liver failure (ALF) remains unknown in a significant proportion of cases. Signs of autoimmunity may be present, but no consistent pattern has been observed. We aimed to analyze if pretransplant immunological findings, human leukocyte antigen (HLA) haplotypes, and clinical features among patients with an unknown etiology differ from those of autoimmune or other known etiologies. We also analyzed whether such signs impact posttransplant biopsy findings or complications. All adult ALF patients undergoing liver transplantation (LT) in Finland during 1987-2015 were followed to 2016. Data were collected from the LT registry, pathology database, and patient records. A total of 124 patients were included in the analysis. Study subgroups were acute autoimmune hepatitis (AIH; n = 25), known non-AIH etiology (n = 54), and unknown etiology (n = 45). The unknown etiology group differed from the known non-AIH group with regard to the following pretransplant autoimmunity-associated features: positive perinuclear anti-neutrophil cytoplasmic antibodies (36% versus 8%; P = 0.02) and higher mean immunoglobulin A (IgA; 3.2 ± 1.7 versus 2.1 ± 1.4, P = 0.006) and immunoglobulin G (IgG; 12.7 ± 4.3 versus 8.5 ± 3.6, P = 0.001). AIH-associated HLA haplotypes B8, DR3, and B8DR3 were more common in the AIH group (40%, 44%, and 36%, respectively) and in the unknown group (29%, 33%, and 29%, respectively) than in the known non-AIH group (11%, 17%, and 11%, respectively) or in the Finnish general population (17%, 18%, and 8%, respectively). However, these findings had no association with protocol biopsies, extrahepatic autoimmune diseases, or survival. Patients with ≥ 1 rejection episode had higher pretransplant IgA (3.7 ± 2.3 versus 2.6 ± 1.2; P = 0.02) and IgG (16.4 ± 10.2 versus 12.4 ± 6.8; P = 0.03) than those without rejections. Autoimmunity-associated pretransplant laboratory findings and HLA haplotypes were common in ALF of unknown etiology, but they showed minimal predictive value for posttransplant biopsy findings, clinical complications, or survival.

Nanoparticle Conjugation of Ginsenoside Rg3 Inhibits Hepatocellular Carcinoma Development and Metastasis

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. The prognosis of HCC remains very poor; thus, an effective treatment remains urgent. Herein, a type of nanomedicine is developed by conjugating Fe@Fe3 O4 nanoparticles with ginsenoside Rg3 (NpRg3), which achieves an excellent coupling effect. In the dimethylnitrosamine-induced HCC model, NpRg3 application significantly prolongs the survival of HCC mice. Further research indicates that NpRg3 application significantly inhibits HCC development and eliminates HCC metastasis to the lung. Notably, NpRg3 application delays HCC-induced ileocecal morphology and gut microbial alterations more than 12 weeks during HCC progression. NpRg3 administration elevates the abundance of Bacteroidetes and Verrucomicrobia, but decreases Firmicutes. Twenty-nine predicted microbial gene functions are enriched, while seven gene functions are reduced after NpRg3 administration. Moreover, the metabolomics profile presents a significant progression during HCC development, but NpRg3 administration corrects tumor-dominant metabolomics. NpRg3 administration decreases 3-indolepropionic acid and urea, but elevates free fatty acids. Importantly, NpRg3 application remodels the unbalanced correlation networks between gut microbiota and metabolism during HCC therapy. In conclusion, nanoparticle conjugation of ginsenoside Rg3 inhibits HCC development and metastasis via the remodeling of unbalanced gut microbiota and metabolism in vivo, providing an antitumor therapy strategy.

Shear-Wave Dispersion Slope from US Shear-Wave Elastography: Detection of Allograft Damage after Liver Transplantation

Background Allograft damage (hepatic parenchymal damage) after liver transplant is associated with the degree of necroinflammation in graft liver. According to a recent animal study, shear-wave dispersion slope obtained at US shear-wave elastography (SWE) is associated with necroinflammatory activity in the liver. Purpose To evaluate the role of shear-wave dispersion slope in detecting allograft damage after liver transplant. Materials and Methods In this prospective study, 104 liver transplant recipients underwent percutaneous liver biopsy for allograft evaluation from December 2017 to November 2018. All participants underwent allograft SWE examination just before liver biopsy, and liver stiffness and shear-wave dispersion slope were obtained. Allograft damage was diagnosed by histopathologic analysis. Clinical and imaging factors related to liver stiffness and shear-wave dispersion slope were determined by multivariable linear regression analysis. Diagnostic performance of each variable in detecting allograft damage was evaluated by comparing area under the receiver operating curve (AUC) values. Results There were 104 study participants (35 women); median age was 56 years (interquartile range, 50-62 years). Allograft damage was found in 46 of 104 (44.2%) of participants. The median liver stiffness (8.2 kPa vs 6.3 kPa; P < .01) and shear-wave dispersion slope (14.4 [m/sec]/kHz vs 10.4 [m/sec]/kHz; P < .01) were higher in participants with allograft damage than in those without damage, respectively. Fibrosis stage was the only determinant factor for liver stiffness (coefficient, 1.8 kPa per fibrosis stage; 95% confidence interval: 0.1, 3.5; P = .03), whereas both fibrosis stage (coefficient, 1.4 [m/sec]/kHz per fibrosis stage; 95% confidence interval: 0.3, 2.6; P = .02) and necroinflammatory activity (coefficient, 1.6 [m/sec]/kHz per necroinflammatory activity grade; 95% confidence interval: 0.5, 2.7; P < .01) affected shear-wave dispersion slope. The AUC for shear-wave dispersion slope in detecting allograft damage was 0.86, which was higher than that of liver stiffness (AUC, 0.75; P < .01). Conclusion Shear-wave dispersion slope determined at US shear-wave elastography may help in detecting allograft damage after liver transplant. © RSNA, 2019 Online supplemental material is available for this article.

Serum Mac-2 binding protein glycosylation isomer predicts the activation of hepatic stellate cells after liver transplantation

BACKGROUND AND AIM

Serum Mac-2 binding protein glycosylation isomer (M2BPGi) is a novel fibrosis marker for various chronic liver diseases. We investigated the ability of M2BPGi to predict liver fibrosis in liver transplant (LT) recipients.

METHODS

A total of 116 liver biopsies were performed in 113 LT recipients. The serum level of M2BPGi was also measured on the same day. The median age at LT and liver biopsy was 1.1 and 11.8 years, respectively. Serum M2BPGi levels and liver fibrosis status using METAVIR fibrosis score were compared. Immunohistological evaluation by anti-α-smooth-muscle actin (αSMA) was performed, and the relationship between αSMA positive rate and serum M2BPGi levels was investigated.

RESULTS

The median M2BPGi level was 0.78 (range, 0.22-9.50), and 65, 29, 16, 5, and 1 patient(s) had METAVIR fibrosis scores of F0, F1, F2, F3, and F4, respectively. In patients with F0 fibrosis, median M2BPGi level was 0.69 and was significantly lower than in patients with F1 (median 0.99, P < 0.01), F2 (median 1.00, P = 0.01), and F3 fibrosis (median 1.53, P < 0.01). Area-under-the-curve analysis of the ability of M2BPGi level to predict liver fibrosis grade were > F1: 0.716, > F2: 0.720, and > F3: 0.900. Three patients with acute cellular rejection showed high levels of M2BPGi, which decreased after the treatment. A positive correlation existed between M2BPGi levels and αSMA positive rate (r²  = 0.715, P < 0.01).

CONCLUSION

Mac-2 binding protein glycosylation isomer is a novel liver fibrosis marker in LT recipients and is also increased in patients with acute liver injuries, especially acute cellular rejection, even when fibrosis is absent.

HLA, Non-HLA Antibodies, and Eplet Mismatches in Pediatric Liver Transplantation: Observations From a Small, Single-Center Cohort

OBJECTIVES

To identify the risk of developing acute rejection, allograft fibrosis, and antibody-mediated rejection, a retrospective review of pediatric patients who underwent liver transplant between July 31, 1998 and February 29, 2016 and had donor-specific antibodies measured at time of liver biopsy was undertaken.

MATERIALS AND METHODS

HLAMatchmaker Software (http://www.hlamatchmaker.net) was used to define epitope mismatches between donors and recipients and to predict de novo donor-specific antibody risk. Epitope mismatches were evaluated for their immunogenicity.

RESULTS

In our group of 42 recipients, 20 (48%) had donor-specific antibodies. Having an antibody against HLA-DQB1*02 was associated with acute rejection (66.6% vs 36%; P = .024). We found that DQ epitope mismatch load was greater in recipients with class II donor-specific antibodies (9.7 vs 3.6; P = .001). HLA-DQ (7.4 vs 3.6; P = .04) and HLA-DR (8.8 vs 3.8; P = .04) epitope mismatch loads were higher in recipients with DQ + DR donor-specific antibodies. A high portal fibrosis score was associated with higher mismatch load at the DQ locus (P = .005) and DQ + DR loci (P = .03). Having > 5 or > 6 epitope mismatch loads at the DQ locus identified a threshold above which development of DQ donor-specific antibodies would occur (area under the curve = 0.878). Mismatches for eplet 4Q, 45GE, 52PQ, and 52PL, thought to be immunodominant epitopes, were observed for several recipients.

CONCLUSIONS

Knowledge of epitope mismatches between recipients and donors may aid transplant physicians in devising immunosuppression strategies.

Clinical and Morphologic Diagnostic Assessments of Liver Diseases After Liver Transplant

OBJECTIVES

At the National Scientific Center of Surgery named A. Syzganova, more than 100 liver transplants have been conducted from 2012 to November 2017. Survival and quality of life of patients in the posttransplant period largely depend on the compliance of patients, monitoring of complications, cause of liver disease, the severity of the condition of patients in the pretransplant period, and the technical features of the operation. The aims of the study were to analyze the results of liver biopsy in patients after liver transplant and to evaluate the value of morphologic studies of the liver for the diagnosis of complications in the posttransplant period.

MATERIALS AND METHODS

Liver transplant recipients undergoing liver biopsy between 2012 and 2017 were analyzed. Our study included 40 liver biopsies in 29 patients after orthotopic liver transplant who fulfilled the inclusion criteria.

RESULTS

In 51.7% of cases in patients (that is, in 15 of 29 patients), biopsy data revealed changes characteristic of rejection. Biliary complications were found in 10.34% of patients, recurrent liver diseases were confirmed in 17.24% of patients, 3.45% of patients had confirmed cholangitis, and 6.90% of patients were diagnosed with liver steatosis.

CONCLUSIONS

Histopathology assessment of allograft liver biopsies plays an important role in the differential diagnosis of posttransplant complications and in identifying the cause of graft damage; having this information can lead to the appropriate therapeutic intervention.

Optimal immunosuppressor induces stable gut microbiota after liver transplantation

AIM

To study the influence of different doses of tacrolimus (FK506) on gut microbiota after liver transplantation (LT) in rats.

METHODS

Specific pathogen-free Brown Norway (BN) rats and Lewis rats were separated into five groups: (1) Tolerance group (BN-BN LT, n = 8); (2) rejection group (Lewis-BN LT, n = 8); (3) high dosage FK506 (FK506-H) group (Lewis-BN LT, n = 8); (4) middle dosage FK506 (FK506-M) group (Lewis-BN LT, n = 8); and (5) low dosage FK506 (FK506-L) group (Lewis-BN LT, n = 8). FK506 was administered to recipients at a dose of 1.0 mg/kg, 0.5 mg/kg, and 0.1 mg/kg body weight for 29 d after LT to the FK506-H, FK506-M, and FK506-L groups, respectively. On the 30th day after LT, all rats were sampled and euthanized. Blood samples were harvested for liver function and plasma endotoxin testing. Hepatic graft and ileocecal tissues were collected for histopathology observation. Ileocecal contents were used for DNA extraction, Real-time quantitative polymerase chain reaction (RT-PCR) and digital processing of denaturing gradient gel electrophoresis (DGGE) profiles and analysis.

RESULTS

Compared to the FK506-H and FK506-L groups, FK506-M was optimal for maintaining immunosuppression and inducing normal graft function; the FK506-M maintained gut barrier integrity and low plasma endotoxin levels; furthermore, DGGE results showed that FK506-M induced stable gut microbiota. Diversity analysis indicated that FK506-M increased species richness and rare species abundance, and cluster analysis confirmed the stable gut microbiota induced by FK506-M. Phylogenetic tree analysis identified crucial bacteria associated with FK506-M; seven of the nine bacteria that were decreased corresponded to Bacteroidetes, while increased bacteria were of the Bifidobacterium species. FK506-M increased Faecalibacterium prausnitzii and Bifidobacterium spp. and decreased Bacteroides-Prevotella and Enterobacteriaceae, as assessed by RT-PCR, which confirmed the crucial bacterial alterations identified through DGGE.

CONCLUSION

Compared to the low or high dosage of FK506, an optimal dosage of FK506 induced immunosuppression, normal graft function and stable gut microbiota following LT in rats. The stable gut microbiota presented increased probiotics and decreased potential pathogenic endotoxin-producing bacteria. These findings provide a novel strategy based on gut microbiota for immunosuppressive dosage assessment for recipients following LT.

Molecular profiling of subclinical inflammatory lesions in long-term surviving adult liver transplant recipients

BACKGROUND & AIMS

Subclinical inflammatory changes are commonly described in long-term transplant recipients undergoing protocol liver biopsies. The pathogenesis of these lesions remains unclear. The aim of this study was to identify the key molecular pathways driving progressive subclinical inflammatory liver allograft damage.

METHODS

All liver recipients followed at Hospital Clínic Barcelona who were >10 years post-transplant were screened for participation in the study. Patients with recurrence of underlying liver disease, biliary or vascular complications, chronic rejection, and abnormal liver function tests were excluded. Sixty-seven patients agreed to participate and underwent blood and serological tests, transient elastography and a liver biopsy. Transcriptome profiling was performed on RNA extracted from 49 out of the 67 biopsies employing a whole genome next generation sequencing platform. Patients were followed for a median of 6.8 years following the index liver biopsy.

RESULTS

Median time since transplantation to liver biopsy was 13 years (10-22). The most frequently observed histological abnormality was portal inflammation with different degrees of fibrosis, present in 45 biopsies (67%). Two modules of 102 and 425 co-expressed genes were significantly correlated with portal inflammation, interface hepatitis and portal fibrosis. These modules were enriched in molecular pathways known to be associated with T cell mediated rejection. Liver allografts showing the highest expression levels for the two modules recapitulated the transcriptional profile of biopsies with clinically apparent rejection and developed progressive damage over time, as assessed by non-invasive markers of fibrosis.

CONCLUSIONS

A large proportion of adult liver transplant recipients who survive long-term exhibit subclinical histological abnormalities. The transcriptomic profile of these patients' liver tissue closely resembles that of T cell mediated rejection and may result in progressive allograft damage.

LAY SUMMARY

A large proportion of adult liver transplant recipients who survive for a long time exhibit subclinical histological abnormalities. The expression profile (a measurement of the activity of genes) of liver tissue from a large fraction of these patients closely resembles the profile of T cell mediated rejection. Liver allografts showing the highest expression levels of rejection-related genes developed progressive damage over time.

Rethinking de novo immune hepatitis, an old concept for liver allograft rejection: Relevance of glutathione S-transferase T1 mismatch

Antibody-mediated rejection (AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histocompatibility complex with the presence of HLA donor-specific antibodies, but also with antigens regarded as “minor”, whose role in AMR has been demonstrated. Among them, antibodies against glutathione S-transferase T1 have been found in 100% of patients with de novo autoimmune hepatitis (dnAIH) when studied. In its latest update, the Banff Working Group for liver allograft pathology proposed replacing the term dnAIH with plasma cell (PC)-rich rejection. Antibodies to glutathione S-transferase T1 (GSTT1) in null recipients of GSTT1 positive donors have been included as a contributory but nonessential feature of the diagnosis of PC-rich rejection. Also in this update, non-organ-specific anti-nuclear or smooth muscle autoantibodies are no longer included as diagnostic criteria. Although initially found in a proportion of patients with PC-rich rejection, the presence of autoantibodies is misleading since they are not disease-specific and appear in many different contexts as bystanders. The cellular types and proportions of the inflammatory infiltrates in diagnostic biopsies have been studied in detail very recently. PC-rich rejection biopsies present a characteristic cellular profile with a predominance of T lymphocytes and a high proportion of PCs, close to 30%, of which 16.48% are IgG4⁺. New data on the relevance of GSTT1-specific T lymphocytes to PC-rich rejection will be discussed in this review.

Histological findings in protocol biopsies following pediatric liver transplant: Low incidence of abnormalities at 5 years

Histological abnormalities, including chronic hepatitis, fibrosis, and steatosis, are increasingly reported in liver biopsies of children after LT. These changes may be progressive and represent a form of rejection. Liver biochemistry is often initially normal. Our LT program began in 2002, utilizing tacrolimus and low-dose steroids for the first year post-LT. Patients undergo a protocol biopsy at 1 year post-LT prior to stopping steroids, then at 5 years and every 5 years thereafter. Target tacrolimus levels are 5-8 μg/L and 3-5 μg/L after 3 and 12 months, respectively. Between 2002 and 2009, 51 LT were performed; 50 (98%) and 49 (96%) patients survived for 1 and 5 years, respectively. A total of 43 patients (median age at LT 2.3 years) underwent a protocol biopsy at 1 year (16 male; median time post-LT 12.5 months), and 44 (20 male; median time post-LT 5.1 years) at 5 years. By 5 years, 3 had transferred to adult services; 1 was re-transplanted for graft failure and 1 moved overseas. Biopsies were reviewed by 2 pathologists. Most patients (31/44) were on tacrolimus monotherapy at 5 years. At 1 and 5 years, 29 of 43 (67.5%) and 31 of 44 (71%) biopsies were normal, respectively. Two of 44 had chronic allograft hepatitis at 5 years. Two of 43 and 1 of 44 had isolated fibrosis, 3 of 43 and 3 of 44 steatosis, and 3 of 43 and 4 of 44 acute rejection at 1 and 5 years, respectively. Other findings included predominantly biliary changes (6/43 & 3/44 at 1 and 5 years, respectively). Tacrolimus levels at 5 years were slightly higher than anticipated (median trough level 5.8 μg/L). With an immunosuppressive regimen of tacrolimus and low-dose steroids for 1 year followed by tacrolimus monotherapy thereafter, the majority of PLB were normal and no progressive changes were observed at 5 years. Compared to other LT programs, we have lower rates of chronic allograft hepatitis, steatosis, and fibrosis at 5 years. However, the tacrolimus levels at 5 years were higher than planned and this may have played a role. Further evaluation is also required to determine the potential long-term adverse effects of corticosteroid use on linear growth and bone mineral density.

Transient elastography for non-invasive evaluation of post-transplant liver graft fibrosis in children

As graft survival in pediatric LT is often affected by progressive fibrosis, numerous centers carry out protocol liver biopsies. Follow-up biopsy protocols differ from center to center, but all biopsies are progressively spaced out, as time from transplant increases. Therefore, there is a need for non-invasive techniques to evaluate graft fibrosis progression in those children who have no clinical or serological signs of liver damage. Indirect markers, such as the APRI, should be relied on with caution because their sensitivity in predicting fibrosis can be strongly influenced by the etiology of liver disease, severity of fibrosis, and patient age. A valid alternative could be TE, a non-invasive technique already validated in adults, which estimates the stiffness of the cylindrical volume of liver tissue, 100-fold the size of a standard needle biopsy sample. The aims of this study were to evaluate the reliability of TE in children after LT and to compare both the TE and the APRI index results with the histological scores of fibrosis on liver biopsies. A total of 36 pediatric LT recipients were studied. All patients underwent both TE and biopsy within a year (median interval -0.012 months) at an interval from LT of 0.36 to 19.47 years (median 3.02 years). Fibrosis was assessed on the biopsy specimens at histology and staged according to METAVIR. There was a statistically significant correlation between TE stiffness values and METAVIR scores (P = .005). The diagnostic accuracy of TE for the diagnosis of significant fibrosis (F ≥ 2) was measured as the area under the curve (AUROC = 0.865), and it demonstrated that the method had a good diagnostic performance. APRI was not so accurate in assessing graft fibrosis when compared to METAVIR (AUROC = 0.592). A liver stiffness cutoff value of 5.6 kPa at TE was identified as the best predictor for a significant graft fibrosis (METAVIR F ≥ 2) on liver biopsy, with a 75% sensitivity, a 95.8% specificity, a 90% positive predictive value, and an 88.5% negative predictive value. These data suggest that TE may represent a non-invasive, reliable tool for the assessment of graft fibrosis in the follow-up of LT children, alerting the clinicians to the indication for a liver biopsy, with the aim of reducing the number of protocol liver biopsies.

A cross-sectional analysis of long-term immunosuppressive regimens after liver transplantation at Asan Medical Center: Increased preference for mycophenolate mofetil

Backgrounds/Aims

Long-term immunosuppression regimens after liver transplantation (LT) are rarely reported in detail. We aimed to provide information on actual long-term immunosuppression regimens through this cross-sectional study.

Methods

Our institutional LT database was searched for adult patients who underwent primary LT operation from 2000 to 2016. We identified 3620 live recipients with actual information on immunosuppressive agent use for 1-17 years.

Results

The study cohort was divided into 7 groups according to posttransplantation period. The immunosuppressive agents used at the cross-sectional review period were tacrolimus in 2884 (79.7%), cyclosporine in 445 (12.3%), mycophenolate mofetil in 2007 (55.4%), and everolimus in 138 (3.8%) recipients. There was no marked difference in immunosuppressive agent use according to pretransplantation liver malignancy or type of LT operation. Tacrolimus, cyclosporine, mycophenolate mofetil, and everolimus were used in 97.4%, 1.8%, 60.9%, and 9.2%, respectively, in the year 2 group; 94.1%, 3.9%, 51.6%, and 8.3%, respectively, in the year 3 group; 87.3%, 8.4%, 68.9%, and 4.8%, respectively, in the year 4-5 group; 78.2%, 12.9%, 64.6%, and 3.0%, respectively, in the year 6-7 group; 76.9%, 10.8%, 58.8%, and 2.4%, respectively, in the year 8-10 group; 66.7%, 22.4%, 43.4%, and 1.5%, respectively, in the year 11-15 group; and 73.8%, 15.4%, 32.9%, and 1.7%, respectively, in the year ≥15 group.

Conclusions

Tacrolimus and mycophenolate mofetil are the primary immunosuppressive agents after LT, and the indications for everolimus have started to increase at our institution. We believe our results will help establish tailored long-term immunosuppression regimens.

Effect of PNPLA3 I148M polymorphism on histologically proven non-alcoholic fatty liver disease in liver transplant recipients

AIM

PNPLA3 I148M polymorphism (rs738409 C>G) is the most important and best-known polymorphism for non-alcoholic fatty liver disease (NAFLD). However, little is known about the effect of this polymorphism on NAFLD after liver transplantation (LT). We aimed to evaluate the association between this polymorphism and post-LT NAFLD.

METHODS

We designed a prospective case-control study. Among adult recipients who underwent LT between April 2014 and October 2015, those whose whole blood was preoperatively collected for genotyping in both recipients and coupled donors and those who underwent protocol biopsy at 1 year post-LT were enrolled.

RESULTS

A total of 32 recipients were enrolled. Histologically proven steatosis (≥5%) was present in 28.1% of patients at a mean time of 12.7 ± 2.0 months after LT. Moderate and more severe steatosis (≥33%) was present in 9.4%. One year after LT, steatosis was present in 50.0% of homozygous recipients with the rs738409-G allele. It was present in 27.3% of heterozygous recipients with the rs738409-G allele, and in 9.1% (P = 0.041) of recipients with rs738409-CC. The genotype of the donor was not significantly (P = 0.647) associated with post-LT NAFLD. When both recipient and coupled donor showed heterogeneous or homozygous genotype of the rs738409-G allele, there was significantly more post-LT NAFLD compared to that in others (47.1% vs. 6.7%; P = 0.018). In univariate and multivariate analyses, only the presence of the rs738409-G risk allele in both donor and recipient was a significant risk factor for post-LT NALFD (relative risk, 26.95; P = 0.048).

CONCLUSIONS

PNPLA3 I148M polymorphism can significantly affect histologically proven NAFLD at 1 year post-LT.

Liver transplantation in adults with liver disease due to common variable immunodeficiency leads to early recurrent disease and poor outcome

Common variable immunodeficiency (CVID) is the most common form of primary immunodeficiency characterized by antibody deficiency, recurrent bacterial infections, and autoimmunity. Advanced chronic liver disease occurs in a subset of patients with CVID and manifests with various histological features, such as nodular regenerative hyperplasia, inflammation, fibrosis, and cholangiopathy. We present a case series characterizing the outcomes in adult patients transplanted for primary CVID-related liver disease. We discuss the unique transplantation challenges faced in this primary immunodeficiency group including susceptibility to infections and early disease recurrence. There is a statistically significant decrease in 3-year and 5-year survival after liver transplantation in those with CVID-related liver disease (55% at 3 and 5 years) compared with all-comers (89% at 3 years, 81% at 5 years), prompting a need for discussion of suitability of transplantation in this group of patients as well as methods for reducing posttransplantation risk such as scrupulous search for infectious agents and reduction of immunosuppression. Liver Transplantation 24 171-181 2018 AASLD.

Gut microbial balance and liver transplantation: alteration, management, and prediction

Liver transplantation is a conventional treatment for terminal stage liver diseases. However, several complications still hinder the survival rate. Intestinal barrier destruction is widely observed among patients receiving liver transplant and suffering from ischemia-reperfusion or rejection injuries because of the relationship between the intestine and the liver, both in anatomy and function. Importantly, the resulting alteration of gut microbiota aggravates graft dysfunctions during the process. This article reviews the research progress for gut microbial alterations and liver transplantation. Especially, this work also evaluates research on the management of gut microbial alteration and the prediction of possible injuries utilizing microbial alteration during liver transplantation. In addition, we propose possible directions for research on gut microbial alteration during liver transplantation and offer a hypothesis on the utilization of microbial alteration in liver transplantation. The aim is not only to predict perioperative injuries but also to function as a method of treatment or even inhibit the rejection of liver transplantation.

Tolerance after liver transplantation: Where are we?

Impeccable management of immunosuppression is required to ensure the best longterm outcomes for liver transplant recipients. This is particularly challenging for children who arguably need 8 decades of graft and patient survival. Too little risks chronic, often subclinical allo-immune injury while too much risks insidious and cumulative toxicities. Historically, immunosuppression minimization or withdrawal has been a strategy to optimize the longevity of liver transplant recipients. The literature is sprinkled with single-center reports of operationally tolerant patients - those with apparently normal liver function and liver tests. However, without biopsy evidence of immunological quiescence, confidence in the phenotypic assignment of tolerance is shaky. More recently, multicenter trials of immunosuppression withdrawal for highly selected, stable, longterm adult and pediatric liver recipients have shown tolerance rates, based on both biochemical and histological assessment, of 40% and 60%, respectively. Extended biochemical and histologic follow-up of children over 8 years, equivalent to 7+ years off of drug, suggests that operational tolerance is robust. Therefore, clearly, immunosuppression can be completely and safety withdrawn from highly-selected subsets of adults and children. However, these trials have also confirmed that clinically ideal recipients - those eligible for immunosuppression withdrawal trial - can harbor significant and worrisome inflammation and/or fibrosis. Although the etiology and prognosis of these findings remain unknown, it is reasonable to surmise that they may reflect an anti-donor immune response that is insufficiently controlled. To achieve the outcomes that we are seeking and that our patients are demanding, we desperately need noninvasive but accurate biomarkers that identify whether immunosuppression is neither too much nor too little but "just right." Until these are available, liver histology remains the gold standard to assess allograft health and guide immunosuppression management. Liver Transplantation 23 1601-1614 2017 AASLD.

Unique clinical conditions associated with different acinar regions of fibrosis in long-term surviving pediatric liver grafts

In the majority of long-term survivors after PLTx, graft fibrosis has been identified. Recently, subtypes of graft fibrosis have been described based on their predominant acinar localization. We aimed to evaluate whether the development of portal, perisinusoidal, and centrilobular distribution of graft fibrosis is related to patient or transplantation-related parameters. We reviewed the histological features in protocol liver biopsies taken at 1 and 5 years after PLTx of 47 children on a tacrolimus-based immunosuppressive regimen. Fibrosis was assessed according to the LAFSc. The prevalence of portal fibrosis increased from 31% to 62%, sinusoidal from 68% to 79%, and centrilobular from 76% to 85%. The presence of portal fibrosis was associated with total bilirubin and γGT levels (each P<.02) and tended to be associated with biliary complications (P=.06). Sinusoidal fibrosis was associated with prior rejection episodes (P<.02) and centrilobular fibrosis with the presence of HLA mismatches (P=.02). In conclusion, using the LAFSc, we found a high incidence of progressive fibrosis in the 1-year and 5-year protocol biopsies after PLTx. Progression of fibrosis was observed in all acinar compartments, and each of the three locations is associated with different clinical conditions.

Combined resistance and endurance training at a moderate-to-high intensity improves physical condition and quality of life in liver transplant patients

Although currently moderate and high intensity concurrent physical exercise is prescribed in populations with special needs due to its greater effect on physical condition and health-related quality of life (HRQOL), there are no data in the liver transplantation (LT) setting. The aim of this study is to evaluate changes in maximal strength, aerobic capacity, body composition, liver function, and HRQOL in LT patients after a moderate-to-high intensity combined resistance-endurance training. Six months after LT, 54 patients were randomized into 2 groups: intervention group (IG) and control group (CG). A total of 50 patients completed the study with repeat testing at 6 and 12 months after LT. The IG completed a 6-month exercise training program, consisting of exercising 2 days for 24 weeks in the hospital facilities, whereas the CG followed usual care recommendations. Patients completed a 5-multijoint exercise circuit with elastic bands involving the major muscle groups. The effects of the concurrent training program on maximal oxygen consumption, overall and regional maximal strength, body composition, liver function, and HRQOL were analyzed. The IG showed a significant improvement (P < 0.05) in outcome measurements compared with the CG in aerobic capacity, hip extension, elbow flexion, overall maximal strength, physical functioning, and vitality of HRQOL, whereas no changes were observed in body composition and liver function tests. In conclusion, this is the first study that combines supervised resistance and aerobic training performed at moderate-to-high intensity in LT recipients. It results in significant improvements in aerobic capacity, maximal strength, and HRQOL. Liver Transplantation 23 1273-1281 2017 AASLD.

T-cell allorecognition of donor glutathione S-transferase T1 in plasma cell-rich rejection

AIM

To investigate the role of glutathione S-transferase T1 donor-specific T lymphocytes in plasma cell-rich rejection of liver allografts.

METHODS

The study group included 22 liver transplant patients. Among them, 18 patients were mismatched for the glutathione S-transferase T1 (GSTT1) alleles (don+/rec-), and 4 were matched (don+/rec+). Seven of the mismatched patients produced anti-GSTT1 antibodies and developed plasma cell-rich rejection (former de novo immune hepatitis). For the detection of specific T lymphocytes, peripheral blood mononuclear cells were collected and stored in liquid nitrogen. The memory T cell response was studied by adding to the cell cultures to a mix of 39 custom-made, 15-mer overlapping peptides, which covered the entire GSTT1 amino acid sequence. The specific cellular response to peptides was analyzed by flow cytometry using the markers CD8, CD4, IL-4 and IFNγ.

RESULTS

Activation of CD8⁺ T cells with different peptides was observed exclusively in the group of patients with plasma-cell rich rejection (3 out of 7), with production of IL-4 and/or IFNγ at a rate of 1%-4.92% depending on the peptides. The CD4⁺ response was most common and not exclusive for patients with the disease, where 5 out of 7 showed percentages of activated cells from 1.24% to 31.34%. Additionally, two patients without the disease but with the mismatch had cells that became stimulated with some peptides (1.45%-5.18%). Highly unexpected was the finding of a double positive CD4⁺CD8^low T cell population that showed the highest degree of activation with some of the peptides in 7 patients with the mismatch, in 4 patients with plasma cell-rich rejection and in 3 patients without the disease. Unfortunately, CD4⁺CD8^low cells represent 1% of the total number of lymphocytes, and stimulation could not be analyzed in 9 patients due to the low number of gated cells. Cells from the 4 patients included as controls did not show activation with any of the peptides.

CONCLUSION

Patients with GSTT1 mismatch can develop a specific T-cell response, but the potential role of this response in the pathogenesis of plasma cell-rich rejection is unknown.

Long-term outcomes of de novo autoimmune hepatitis in pediatric liver transplant recipients

The long-term course and outcome of DAIH is unknown. A retrospective multicenter study assessing associations and long-term consequences of DAIH developing in a transplanted allograft is presented. Children with DAIH were followed from diagnosis until death, re-LT, or transfer of care and for a minimum of 1 year. A total of 31 patients of 1833 (1.7%) LT were identified; 29 followed for a median of 7.1 years (range, 1.6-15); 52% had no rejection preceding diagnosis of DAIH. Transaminases fell following treatment with steroids and antimetabolites (ALT 108 vs 39 U/L (P=.002); AST 112 vs 52 U/L (P=.003); GGT 72 vs 36 U/L (P=.03), but this was not universally sustained. Transaminases >2X ULN observed in 38% of patients at last follow-up; commonly GGT, attributed to bile duct injury and ductopenia. Portal hypertension (PHT) was seen in four patients and associated with severe fibrosis and cirrhosis. Re-LT occurred in two patients for chronic rejection (CR) and uncontrolled PHT with gastrointestinal bleeding, respectively. No deaths from DAIH were reported. DAIH is an uncommon complication following pediatric LT requiring prolonged and augmented immunosuppression. It is associated with continued allograft dysfunction and may lead to bile duct injury, CR, and PHT necessitating re-LT.

The use of old donors in liver transplantation

The process of ageing has an impact on the entire human body including the organ systems. In transplantation, professionals are daily faced with risk assessment of suitable donor offers , whether to accept a liver graft for a specific recipient. In this context, livers from elderly donors are more frequently accepted for transplantation, to increase the donor pool and compensate the high waiting list mortality. In the current practice it is not unusual to accept 60-year old donor livers for transplantation, as the donor demographics have significantly changed over the years. However, controversy exists regarding the use of livers from donors above 70 or 80 years, particular in combination with other risk factors, e.g. liver steatosis, warm ischaemia or long cold storage. This review focuses first on the impact of ageing on liver morphology and function. Second, we will highlight outcome after transplantation from elderly donors. Finally, we describe further risk factors and donor-recipient selection under the scope of old donor organs and include our institutional experience and policy.

Practical Recommendations for Long-term Management of Modifiable Risks in Kidney and Liver Transplant Recipients: A Guidance Report and Clinical Checklist by the Consensus on Managing Modifiable Risk in Transplantation (COMMIT) Group

Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs available for transplant. The clinical transplant community needs to identify and manage those patient modifiable factors, to decrease the risk of graft failure, and improve longer-term outcomes.COMMIT was formed in 2015 and is composed of 20 leading kidney and liver transplant specialists from 9 countries across Europe. The group's remit is to provide expert guidance for the long-term management of kidney and liver transplant patients, with the aim of improving outcomes by minimizing modifiable risks associated with poor graft and patient survival posttransplant.The objective of this supplement is to provide specific, practical recommendations, through the discussion of current evidence and best practice, for the management of modifiable risks in those kidney and liver transplant patients who have survived the first postoperative year. In addition, the provision of a checklist increases the clinical utility and accessibility of these recommendations, by offering a systematic and efficient way to implement screening and monitoring of modifiable risks in the clinical setting.

Contrast-Enhanced Ultrasound Using Perfluorobutane-Containing Microbubbles in the Assessment of Liver Allograft Damage: An Exploratory Prospective Study

This prospective study investigated the usefulness of contrast (perfluorobutane-containing microbubbles)-enhanced ultrasound in the non-invasive assessment of liver allograft damage. Forty-one liver recipients underwent contrast-enhanced ultrasound followed by a liver biopsy. The hepatic filling rate (time between the arrival of contrast agent in the right hepatic artery and the maximum intensity of hepatic parenchyma) and parenchymal intensity difference before and after instantaneous high-power emission in the Kupffer phase were measured. Patients with allograft damage had higher hepatic filling rates and lower parenchymal intensity differences than those without damage (42.0 ± 16.9 vs. 30.5 ± 7.7 s, p = 0.005; 6.1 ± 7.4 vs. 16.6 ± 16.1 dB, p = 0.047, respectively). In the diagnosis of liver allograft damage, hepatic filling rate and parenchymal intensity difference had sensitivities of 61.5% and 90.9% and specificities of 92.6% and 63.6% using cutoffs of >38.5 s and ≤10.3 dB, respectively. In conclusion, contrast-enhanced ultrasound may be a promising tool in the detection of liver allograft damage.