‘De novo’ and ‘recurrent’ autoimmune hepatitis after liver transplantation: A comprehensive review

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Antigen-specific T cells and autoimmunity

Autoimmune diseases (ADs) showcase the intricate balance between the immune system's protective functions and its potential for self-inflicted damage. These disorders arise from the immune system's erroneous targeting of the body's tissues, resulting in damage and disease. The ability of T cells to distinguish between self and non-self-antigens is pivotal to averting autoimmune reactions. Perturbations in this process contribute to AD development. Autoreactive T cells that elude thymic elimination are activated by mimics of self-antigens or are erroneously activated by self-antigens can trigger autoimmune responses. Various mechanisms, including molecular mimicry and bystander activation, contribute to AD initiation, with specific triggers and processes varying across the different ADs. In addition, the formation of neo-epitopes could also be implicated in the emergence of autoreactivity. The specificity of T cell responses centers on the antigen recognition sequences expressed by T cell receptors (TCRs), which recognize peptide fragments displayed by major histocompatibility complex (MHC) molecules. The assortment of TCR gene combinations yields a diverse array of T cell populations, each with distinct affinities for self and non-self antigens. However, new evidence challenges the traditional notion that clonal expansion solely steers the selection of higher-affinity T cells. Lower-affinity T cells also play a substantial role, prompting the "two-hit" hypothesis. High-affinity T cells incite initial responses, while their lower-affinity counterparts perpetuate autoimmunity. Precision treatments that target antigen-specific T cells hold promise for avoiding widespread immunosuppression. Nevertheless, detection of such antigen-specific T cells remains a challenge, and multiple technologies have been developed with different sensitivities while still harboring several drawbacks. In addition, elements such as human leukocyte antigen (HLA) haplotypes and validation through animal models are pivotal for advancing these strategies. In brief, this review delves into the intricate mechanisms contributing to ADs, accentuating the pivotal role(s) of antigen-specific T cells in steering immune responses and disease progression, as well as the novel strategies for the identification of antigen-specific cells and their possible future use in humans. Grasping the mechanisms behind ADs paves the way for targeted therapeutic interventions, potentially enhancing treatment choices while minimizing the risk of systemic immunosuppression.

Mechanisms of Tolerance Induction in Liver Transplantation: Lessons Learned from Fetomaternal Tolerance, Autoimmunity and Tumor Immunity

Since the first published report of experimental kidney transplantation in dogs in 1902, there were many experimental and clinical trials of organ transplantation, with many sacrifices. After the establishment of the surgical technique and the discovery of immunosuppressive drugs, transplantation became the definitive treatment strategy for patients with terminal organ failure. However, this is not a common therapy method due to the difficulty of solving the fundamental issues behind organ transplantation, including the shortage of donor graft, potential risks of transplant surgery and economic capability. The pre- and post-transplant management of recipients is another critical issue that may affect transplant outcome. Most liver transplant recipients experience post-transplant complications, including infection, acute/chronic rejection, metabolic syndrome and the recurrence of hepatocellular carcinoma. Therefore, the early prediction and diagnosis of these complications may improve overall and disease-free survival. Furthermore, how to induce operational tolerance is the key to achieving the ultimate goal of transplantation. In this review, we focus on liver transplantation, which is known to achieve operational tolerance in some circumstances, and the mechanical similarities and differences between liver transplant immunology and fetomaternal tolerance, autoimmunity or tumor immunity are discussed.

Liver Transplant in Patients With Autoimmune Hepatitis: A Large Single-Center Study

OBJECTIVES

Autoimmune hepatitis is a rare indication for liver transplant in Western countries. Our goal was to identify characteristics and long-term outcomes of patients who underwent liver transplant for autoimmune hepatitis-related end-stage liver disease at our center.

MATERIALS AND METHODS

Adult patients who underwent primary liver transplant from January 2007 to March 2022 at Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran, were enrolled in our study.

RESULTS

Among 1107 patients enrolled in our study, mean age was 45.94 ± 12.43 years (range, 16-73 years) and 423 (38.2%) female patients were included. Autoimmune hepatitis was the underlying cause of cirrhosis in 177 patients (experimental group); the other 930 patients did not have autoimmune hepatitis (control group). All patients were followed for a median of 60 ± 40.3 months (range, 3-187 months) after transplant. In the experimental group, patient survival rates at 1 month, 1 year, and 3 years were 87%, 81%, and 78%, which were not significantly different between the 2 groups (P = .445). Recurrence of autoimmune hepatitis was detected in 8 patients (4.5%) in the experimental group. Acute allograft rejection was more significantly detected in the patients with recurrence of autoimmune hepatitis than in patients without recurrence of autoimmune hepatitis.

CONCLUSIONS

Liver transplant in patients with autoimmune hepatitis is safe and is associated with good outcomes.

Molecular mimicry and autoimmunity in the time of COVID-19

Infectious diseases are commonly implicated as potential initiators of autoimmune diseases (ADs) and represent the most commonly known factor in the development of autoimmunity in susceptible individuals. Epidemiological data and animal studies on multiple ADs suggest that molecular mimicry is one of the likely mechanisms for the loss of peripheral tolerance and the development of clinical disease. Besides molecular mimicry, other mechanisms such as defects in central tolerance, nonspecific bystander activation, epitope-determinant spreading, and/or constant antigenic stimuli, may also contribute for breach of tolerance and to the development of ADs. Linear peptide homology is not the only mechanism by which molecular mimicry is established. Peptide modeling (i.e., 3D structure), molecular docking analyses, and affinity estimation for HLAs are emerging as critical strategies when studying the links of molecular mimicry in the development of autoimmunity. In the current pandemic, several reports have confirmed an influence of SARS-CoV-2 on subsequent autoimmunity. Bioinformatic and experimental evidence support the potential role of molecular mimicry. Peptide dimensional analysis requires more research and will be increasingly important for designing and distributing vaccines and better understanding the role of environmental factors related to autoimmunity.

Autoimmune hepatitis and liver transplantation: Indications, and recurrent and de novo autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory disease of the liver that is characterized by circulating autoantibodies and elevated serum globulin levels. Liver transplantation may be required for patients with acute liver failure, decompensated cirrhosis, and hepatocellular carcinoma. Recurrence is defined as development of the same disease in the allograft following liver transplantation. Autoimmune hepatitis recurs in 36%-68% of the recipients 5 years after liver transplantation. De novo autoimmune hepatitis is the development of autoimmune hepatitis like clinical and laboratory characteristics in patients who had undergone liver transplantation for causes other than autoimmune hepatitis. Diagnostic work up for recurrent and de novo autoimmune hepatitis is similar to the diagnosis of the original disease, and it is usually difficult. Predniso(lo)ne with or without azathioprine is the main treatment for recurrent and de novo autoimmune hepatitis. Early diagnosis and treatment are vital for patient prognosis because de novo autoimmune hepatitis and recurrent autoimmune hepatitis cause graft loss and result in subsequent retransplantation if medical treatment fails.

Differential IgG4-Producing Plasma Cell Infiltration in Non- and Post-Transplant Plasma Cell Hepatitis

Autoimmune hepatitis (AIH), post-transplant recurrent AIH (rAIH), and plasma cell-rich rejection (PCR) are clinical diagnoses with the shared histopathologic hallmark of plasma cell hepatitis (PCH). As these histologically and serologically indistinguishable diagnoses are differentiated by clinical context, it remains uncertain whether they represent distinct immunologic phenomena. Improved understanding of immunoglobulin subclass 4-producing plasma cells (IgG4-PC) has brought attention to IgG4 as an immunophenotypic biomarker. To date, degree and clinical significance of IgG4-PC infiltration in PCH remain elusive. This retrospective, single-center study assessed IgG4-PC infiltration in AIH, rAIH, and PCR via standardized immunohistochemistry analysis. Identified cases from 2005 to 2020 (n = 47) included AIH (treatment-naïve AIH (tnAIH): n = 15 and AIH-flare on treatment (fAIH); n = 10), rAIH (n = 8), and PCR (n = 14) were analyzed and correlated with clinical characteristics. IgG4-Positivity (# IgG4-PC/# pan-IgG-expressing cells) distribution was heterogenous and overlapping [tnAIH: 0.060 (IQR 0.040-0.079), fAIH: 0.000 (0.000-0.033), rAIH: 0.000 (0.000-0.035), PCR: 0.228 (0.039-0.558)]. IgG4-Positivity was inversely correlated with corticosteroid use (p < 0.001). IgG4-Positivity ≥0.500 was associated with rapid AST improvement (p = 0.03). The variable IgG4-Positivity of AIH, rAIH and PCR suggests diverse and overlapping immunopathologic mechanisms and that current diagnostic schemes inadequately capture PCH immunopathology. We propose incorporation of IgG4-Positivity to refine current PCH classification and treatment strategies.

Ginsenosides Regulates Innate Immunity to Affect Immune Microenvironment of AIH Through Hippo-YAP/TAZ Signaling Pathway

Autoimmune hepatitis (AIH) is characterized by chronic progressive liver inflammatory, but there is still no safe and effective medicine. Therefore, glucocorticoid remains the top choice for AIH treatment. In previous studies, it has been confirmed that ginsenosides (GSS) can produce glucocorticoid-like effects and therapeutic effects on various autoimmune diseases. However, the mechanism of GSS for AIH remains unclear. As an important part of the innate immune system, bone marrow-derived suppressor cells (MDSC) have been identified as an important driver of follow-up acquired immune response in many autoimmune diseases, including AIH. Herein, it was found out that GSS intervention can be effective in regulating the immune microenvironment and liver impairment induced by Con A in AIH mice. In vitro, the MDSCs derived from healthy mice and the T cells deried from AIH mice were co-cultured. Then, different drugs were intervened with to explore the therapeutic mechanism. Besides, the proliferation and differentiation of MDSCs and T cells were analyzed by flow cytometry, while GR, Hippo-YAP signal pathway and the expression of MDSC-related genes and proteins were detected through qRT-PCR and Western Blot. The changes in NO and ROS levels were further analyzed. The trend of related cytokines expression (IFN- γ, TGF- β, IL-10, IL-6, IL-17) was detected by ELISA. Furthermore, an analysis was conducted as to the ALT and liver pathology of mice for evaluating the liver function of mice. It was discovered that MDSCs proliferation was inhibited, and that T cells tended to differentiate into Th17 rather than Treg in AIH mice. Moreover, the intervention of GSS activated GR and Yap, in addition to promoting the proliferation of MDSCs, especially M-MDSCs. This further promoted the differentiation of Treg to enable immune tolerance, thus alleviating liver impairment. Therefore, it was proposed that GSS can alleviate AIH by modulating the innate immunity and adaptive T cell immunity, which may be the underlying mechanism for GSS to mitigate the liver impairment induced by AIH.

Diagnostic and prognostic scoring systems for autoimmune hepatitis: a review

INTRODUCTION

Auto-immune hepatitis (AIH) is a rare condition which primarily affects young women. Several diagnostic scoring systems exist based on clinical, biochemical, immunologic and histologic characteristics of AIH. Additionally, prognostic parameters can be identified. The purpose of this literature review is to compare the clinical value, strengths and limitations of these diagnostic and prognostic scoring systems.

METHODS

A literature search was performed in two databases and selected based on diagnostic and prognostic criteria. Only studies concerning AIH in adults were included.

RESULTS

The backbone of scoring systems remains the revised AIH criteria published in 1999 and the simplified from 2008. The revised system shows a higher sensitivity, lower specificity and lower diagnostic accuracy compared to the simplified. Limitations to these scoring systems include limited diagnostic accuracy in acute or fulminant liver failure, insufficient inclusion of atypical auto-antibodies and lacking diagnostic power in presence of overlap syndromes. Concerning these overlap syndromes, the Paris criteria show a higher diagnostic accuracy compared to the scoring systems for AIH. Presently, no clinical prognostic scoring systems are available. However, a first system based on response to treatment accurately predicts long-term survival in AIH.

CONCLUSION

Diagnostic scoring systems are useful in diagnosing AIH and have complementary value. However, they are no substitute for the gold standard of appropriate clinical assessment and are mostly useful in defining cohorts for research purposes. An evolution towards a more dynamic scoring system, using prognostic parameters and the progression of typical features, seems more valuable than the current diagnostic systems.

Gut Microbiota and Chemical-Induced Acute Liver Injury

Background: Drug overdose or chemical exposures are the main causes of acute liver injury (ALI). Severe liver injury can develop into liver failure that is an important cause of liver-related mortality in intensive care units in most countries. Pharmacological studies have utilized a variety of comprehensive chemical induction models that recapitulate the natural pathogenesis of acute liver injury. Their mechanism is always based on redox imbalance-induced direct hepatotoxicity and massive hepatocyte cell death, which can trigger immune cell activation and recruitment to the liver. However, the pathogenesis of these models has not been fully stated. Many studies showed that gut microbiota plays a crucial role in chemical-induced liver injury. Hepatotoxicity is likely induced by imbalanced microbiota homeostasis, gut mucosal barrier damage, systemic immune activation, microbial-associated molecular patterns, and bacterial metabolites. Meanwhile, many preclinical studies have shown that supplementation with probiotics can improve chemical-induced liver injury. In this review, we highlight the pathogenesis of gut microorganisms in chemical-induced acute liver injury animal models and explore the protective mechanism of exogenous microbial supplements on acute liver injury.

Incidence of de novo autoimmune hepatitis in children and adolescents with increased autoantibodies after liver transplantation: a meta-analysis

The objective of this meta-analysis was to assess the incidence of de novo autoimmune hepatitis (AIH) in children and adolescents with increased autoantibodies after liver transplantation. We systematically retrieved studies from PubMed, Embase, Central, CNKI, VIP and Wanfang published before February 1, 2020. All analyses were conducted using R-4.0.1 statistical package (Meta). Seven studies with high quality were pooled in our final analysis (N = 251 participants). The incidence of de novo AIH was 9% [95% confidence interval (CI) 1-23%, I²  = 86%]. Subgroup analysis suggested that publications not using the International Autoimmune Hepatitis Group (IAIHG) criteria have marginally significantly higher incidence of de novo AIH than those using IAIHG criteria (P for interaction = 0.08). The incidence of chronic rejection was 8% (95% CI 2-17%, I²  = 72%). Meta-regression indicated significant correlation (P = 0.04; estimate: 1.51) between the incidence of de novo AIH and the rate of increase of antibodies to liver/kidney microsome (anti-LKM). It is still challenging to distinguish de novo AIH and chronic rejection in children and adolescents with increased autoantibodies after liver transplantation. The diagnostic criteria for de novo AIH in children and adolescents and the role of anti-LKM in the development of de novo AIH deserve future investigation.

Recurrent Autoimmune Hepatitis and De Novo Autoimmune Hepatitis in the Liver Allograft

OBJECTIVES

Autoimmune hepatitis (AIH) is a form of severe hepatitis that can recur after orthotopic liver transplant (OLT). Presentation of AIH in patients with OLT who do not have a history of AIH is called de novo AIH (DNAIH). We evaluated the clinicopathologic characteristics of AIH and DNAIH.

METHODS

Clinicopathologic and outcome measures of 11 patients with recurrent AIH (RAIH) and 22 with DNAIH identified between 2000 and 2017 were compared.

RESULTS

Both cohorts showed female predominance. The mean clinical follow-up was 13 and 7.8 years in the in the RAIH and DNAIH groups, respectively (P = .1). Moderate portal inflammation was more common in patients with RAIH (64% vs 27%, P = .043). A trend was observed for more cases of DNAIH showing severe inflammation (36% vs 9%, P = .09) and submassive necrosis compared with RAIH (23% vs 0%, P = .086). A trend for more advanced fibrosis was also noted in the RAIH group (27% vs 5%, P = .059). Three patients with RAIH lost their grafts because of RAIH. Five-year disease-specific graft survival (GS) (P = .012) and overall GS (P = .015) were worse in patients with RAIH. Complement component 4d immunohistochemistry was positive in 2 patients with RAIH and 3 with DNAIH but showed no correlation with GS or other parameters.

CONCLUSIONS

RAIH seems to have a more aggressive clinical course than DNAIH and warrants closer clinical follow-up and aggressive treatment.

Approach to the patient with acute severe autoimmune hepatitis

Autoimmune hepatitis is associated with varied clinical presentations and natural history, as well as somewhat unpredictable treatment responses. Understanding how to stratify patients who require further escalation of therapy will help clinicians manage these patients. The presentation of acute severe autoimmune hepatitis (AS-AIH) is relatively uncommon, although its prevalence is potentially greater than currently perceived. Previous studies consist of small retrospective single-centre series and are not directly comparable due to the diversity of presentations, disease definitions and non-standardised treatment regimens. We define AS-AIH as those who present acutely with AIH and are icteric with an international normalised ratio ≥1.5 and no evidence of hepatic encephalopathy. Those with hepatic encephalopathy should be defined as having AS-AIH with acute liver failure. In this review, we provide a structured practical approach for diagnosing and managing this unique group of patients.

Autoimmune Hepatitis in Cuban Patients: A Retrospective Analysis of Clinical and Histological Profiles, Treatments, and Outcomes

BACKGROUND

Population-based studies on the clinical course and prognosis of autoimmune hepatitis (AIH) from Caribbean countries are limited.

OBJECTIVE

The aim of this study was to provide information regarding the clinical and laboratory findings, histological profile, treatments, and outcomes of patients with AIH with long-term follow-up in a tertiary referral center.

METHODS

A retrospective study was performed at the National Institute of Gastroenterology in Havana, Cuba, by enrolling 82 patients with a well-documented, long-term clinical course of AIH. Clinical and laboratory findings, histological profiles, treatments, and outcomes were analyzed.

RESULTS

At diagnosis, 73 (89%) patients had AIH type 1, 84.1% were women, and their median age was 46.5 years (range, 17-79 years). The median follow-up period was 84 months (interquartile range, 12-276 months). Clinical onset was mild or subclinical in 72% of patients and asymptomatic in 12.2%. At diagnosis, the Hennes's median score was 6 (range, 3-8). Complications were seen in 44 (53.6%) patients, 42 (51.2%) with liver-related complications and 9 (10.9%) without liver-related complications. Cirrhosis was present at diagnosis in 32 (39%) patients. Cirrhosis was subsequently diagnosed in the other 28 patients who were not cirrhotic at diagnosis, over a median follow-up of 12 (IQR, 2-84) months. During follow-up, 6 patients died (7.3%). Cumulative survival at 5 and 10 years was 98.4% and 89%, respectively. A complete biochemical response was achieved in 79% of patients in a mean (SD) of 11.7 (11.6) months. Side effects due to treatment were reported in 76 (92.7%) patients, and no pretreatment factors were found to predict treatment response.

CONCLUSIONS

These Cuban patients with AIH had acceptable disease remission rate and a prompt treatment response. Although most patients had advanced-stage liver disease at diagnosis or developed during follow-up, the cumulative survival rate was high when patients were receiving and complying with treatment.

Single-Center North American Experience of Liver Transplantation in Autoimmune Hepatitis: Infrequent Indication but Good Outcomes for Patients

Background and Aims

A 40% risk of disease recurrence post-liver transplantation (LT) for autoimmune hepatitis (AIH) has been previously reported. Risk factors for recurrence and its impact on long-term patient outcome are poorly defined. We aimed to assess prevalence, time to disease recurrence, as well as patient and graft survival in patients with recurrent AIH (rAIH) versus those without recurrence.

Methods

Single-center retrospective study of adult recipients who underwent LT for AIH between January 2007 and December 2017. Patients with AIH overlap syndromes were excluded.

Results

A total of 1436 LTs were performed during the study period, of whom 46 (3%) for AIH. Eight patients had AIH overlap syndromes and were excluded. Patients were followed up for 4.4 ± 3.4 years and mean age at LT was 46.8 years. Average transplant MELD (Model for End-Stage Liver Disease) score was 24.9. About 21% of patients (8 of 38) were transplanted for acute onset of AIH; 66% of patients (n = 25) received a deceased donor liver graft, and 34% a living donor organ. rAIH occurred in 7.8% (n = 3/38) of recipients. Time to recurrence was 1.6, 12.2 and 60.7 months. Patient and graft survival in patients without recurrence was 88.6% and 82.8% in 5 years, whereas in those with rAIH, it was 66.7%, respectively.

Conclusion

Although AIH recurs post-LT, our data indicate a lower recurrence rate when compared to the literature and excellent patient and graft survival.

Autoimmune Hepatitis: 2019 Update

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease, characterized by the elevation of aminotransferases, presence of anti-nuclear antibody or anti-smooth muscle antibody, elevated immunoglobulin G (IgG), and interface hepatitis/plasma-lymphocytic inflammation based on histology. Recent epidemiological studies have indicated an increasing trend in the prevalence of AIH worldwide, especially in male patients; this trend may suggest the alteration of environmental triggers of disease onset over time. As no disease-specific biomarker or histological finding is currently available, AIH requires a clinical diagnosis, and a validated diagnostic scoring system with acceptable specificity and sensitivity has been proposed. Regarding treatment, corticosteroids and azathioprine are recommended, and in those who exhibit an incomplete response or those who are intolerant to these drugs, second-line therapy, such as mycophenolate mofetil, is considered. Overall, the long-term outcome is excellent in patients with complete biochemical responses, while life-long maintenance treatment may be required since the cessation of immunosuppressive agents frequently leads to the relapse of the disease. Acute-onset AIH does occur, and the diagnosis is very challenging due to the lack of serum autoantibodies or elevated IgG. The unmet needs include earlier diagnosis, intervention with disseminated clinical practice guidelines, and recognition and improvement of patients’ health-related quality of life with the development of novel corticosteroid-free treatment regimens.

High Frequency of Concomitant Food Allergy Development and Autoantibody Formation in Children Who Have Undergone Liver Transplantation

BACKGROUND

Allergy and other immune-mediated diseases are more frequently reported in children who have undergone liver transplantation. Furthermore, autoantibodies are also prevalent, suggesting a state of immune dysregulation in these patients. Whether or not these processes occur simultaneously in the same individual has not been studied previously.

METHODS

A cohort of 43 children who had undergone liver transplantation for nonautoimmune liver disease at median age of 1.3 years was investigated for allergy and autoimmune disease. Sensitization to food and inhalant allergens was assessed, and autoantibodies were measured.

RESULTS

The prevalence of food allergy was 26% and that of respiratory allergy was 23%, whereas 33% and 26% of the subjects were sensitized to food and inhalant allergens, respectively. Autoimmune disease (ie, autoimmune hepatitis) occurred in a single individual (2%), whereas autoantibodies were present in 44% of the children. Food allergy and autoantibodies occurred concomitantly in 19% of the children, which was almost twice the frequency expected by chance (11%, P = 0.04). Respiratory allergy and the presence of autoantibodies were unrelated (12% concurrence versus the expected 10%, P = 0.73). In the logistic regression analysis, autoantibody formation was associated with discontinued immunosuppression and food allergy, with odds ratios of 13 (P = 0.01) and 7.1 (P = 0.03), respectively.

CONCLUSIONS

In contrast to respiratory allergy, food allergy and autoantibody formation occurred together in the same children who underwent liver transplantation at a frequency higher than would be expected by chance. This may reflect an underlying immune dysregulation that impairs immune tolerance to both food allergens and autoantigens.

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.

A case of acute liver failure due to hepatitis E virus, liver transplantation, and development of de novo autoimmune hepatitis

Acute hepatitis E virus (HEV) infection could lead to acute liver failure (ALF), which requires liver transplantation (LT). HEV infection could progress to chronic infection in an immunosuppressed host. De novo autoimmune hepatitis (AIH) is a rare occurrence of AIH during post-LT immunosuppressive therapy in patients who underwent LT due to not AIH but some other etiology. Here, we report the first case of ALF due to HEV infection, the recurrence of HEV after LT that responded to ribavirin therapy, and then the development of de novo AIH showing a complete response to glucocorticoid therapy but multiple relapses after steroid withdrawal. This peculiar case suggests that HEV could have a pathogenic role in the development of the de novo AIH; additionally, this case report could help clinicians make therapeutic decisions in the post-LT condition.

Autoimmune Hepatitis-Immunologically Triggered Liver Pathogenesis-Diagnostic and Therapeutic Strategies

Autoimmune hepatitis (AIH) is a severe liver disease that arises in genetically predisposed male and female individuals worldwide. Diagnosis of AIH is made clinically applying diagnostic scores; however, the heterotopic disease phenotype often makes a rapid determination of disease challenging. AIH responds favorably to steroids and pharmacologic immunosuppression, and liver transplantation is only necessary in cases with acute liver failure or end-stage liver cirrhosis. Recurrence or development of de novo AIH after transplantation is possible, and treatment is similar to standard AIH therapy. Current experimental investigations of T cell-mediated autoimmune pathways and analysis of changes within the intestinal microbiome might advance our knowledge on the pathogenesis of AIH and trigger a spark of hope for novel therapeutic strategies.

Recurrent Idiopathic Liver Allograft Failure

OBJECTIVES

Many transplant programs have had patients who develop idiopathic recurrent liver allograft failure, necessitating serial transplants, and are deemed to have refractory or recurrent rejection. The frequency and the etiology of this immunologic dysfunction have not been well characterized.

METHODS

Herein, we illustrate the case of a patient who required three retransplants over a period of 20 years for recurrent liver allograft failure. By extensively compiling the patient's many liver biopsy specimens and explants over time, we demonstrate that antibody-mediated rejection (AMR) was a major contributing factor from the outset. We conducted a review of the Scientific Registry for Transplant Recipients database to estimate the potential frequency of AMR.

RESULTS

As illustrated by this case, AMR has varied histologic findings in the setting of elevated donor-specific antibody titers.

CONCLUSIONS

The cause of recurrent allograft failure in this patient was likely a combination of acute cellular rejection and AMR, manifestations of likely underlying immune dysregulation. Pathologists and transplant physicians should recognize the variable histologic presentations of AMR, which is imperative for its timely intervention. This case demonstrates how difficult the diagnosis of AMR can be to make, highlighting the need for strong clinical suspicion in patients having difficult-to-treat rejection and recurrent allograft failure.

Diagnostic Biomarkers to Diagnose Acute Allograft Rejection After Liver Transplantation: Systematic Review and Meta-Analysis of Diagnostic Accuracy Studies

Objective: A systematic review and meta-analysis of diagnostic biomarkers for noninvasive diagnosis of acute allograft rejection following liver transplantation.

Background: Noninvasive blood and urine markers have been widely explored in recent decades for diagnosing acute rejection after liver transplantation. However, none have been translated into routine clinical use so far due to uncertain diagnostic accuracy, and liver biopsy remains the gold standard.

Methods: Systematic literature searches of Medline, Cochrane and Embase were conducted up to February 2019 to identify studies evaluating the use of noninvasive markers in diagnosing allograft rejection following liver transplantation. Meta-analysis was performed using a random effects model with DerSimonian–Laird weighting and the hierarchical summary receiver operating curve.

Results: Of 560 identified studies, 15 studies (1,445 patients) met the inclusion criteria. The following markers were tested: acid labile nitroso-compounds (NOx), serum amyloid A protein, procalcitonin, peripheral blood eosinophil count, peripheral blood T-cell activation and interleukin 2 (IL-2) receptor, guanylate-binding protein-2 mRNA, graft-derived cell-free DNA, pi-glutathione S-transferase, alpha-glutathione S-transferase and serum HLA class I soluble antigens. Only eosinophil count was tested in multiple studies, and they demonstrated high heterogeneity (I² = 72% [95% CI: 0.5–0.99]). IL-2 receptor demonstrated the highest sensitivity (89% [95% CI: 0.78–0.96]) and specificity (81% [95% CI: 0.69–0.89]).

Conclusion: IL-2 receptor expression demonstrated the highest diagnostic accuracy, while the peripheral eosinophil count was the only marker tested in more than one study. Presently, liver biopsy remains superior to noninvasive diagnostic biomarkers as most studies exhibited inferior designs, hindering possible translation into clinical application.

Autoimmune Hepatitis, Sclerosing Cholangitis, and Autoimmune Sclerosing Cholangitis or Overlap Syndrome

Autoimmune hepatitis (AIH) is characterized by elevated serum aminotransferases, immunoglobulin G, autoantibodies, and interface hepatitis, in the absence of a known diagnosis. Presentation is varied. Therapy is with immunosuppression. There is inflammation of the intrahepatic and/or extrahepatic bile ducts in Sclerosing cholangitis (SC) and when associated with inflammatory bowel disease, it is known as primary SC, with Ursodeoxycholic acid used for therapy. The overlap of clinical, biochemical and histological features of AIH and PSC is known as autoimmune sclerosing cholangitis (ASC) or overlap syndrome. Liver transplantation is performed when medical treatment fails and both AIH and PSC may recur post-transplantation.

The Clinical Significance of GP73 in Immunologically Mediated Chronic Liver Diseases: Experimental Data and Literature Review

There is significant void in establishing validated non-invasive surrogate biomarkers of liver fibrosis/cirrhosis in chronic liver diseases (CLD). Golgi protein 73 (GP73) has been suggested as a potential serum marker for the diagnosis of hepatocellular carcinoma (HCC). However, significant background of cirrhosis could have accounted for the elevation of serum GP73 in HCC. In this study, we have taken advantage of a well-defined extensive cohort of 3044 patients with either compensated cirrhosis (n = 1247), decompensated cirrhosis (n = 841) or pre-cirrhotic CLD (n = 956) and our ability to quantify serum GP73 to define the potential of serum GP73 as a biomarker of liver cirrhosis/fibrosis in CLD. The diagnostic value of GP73 was compared with aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis index based on four factors (FIB-4) and liver stiffness measurement (LSM). Immunohistochemical analysis was performed to measure hepatic GP73 expression. Receiver operating characteristic curve analysis demonstrated that serum GP73 had a good diagnostic potential for compensated cirrhosis regardless of etiology. The diagnostic performance of GP73 is better than APRI, FIB-4 and similar with LSM, especially in patients with severe inflammation, steatosis and cholestasis. Notably, in patients of autoimmune liver diseases, non-alcoholic fatty liver disease and viral hepatitis, serum GP73 also exhibited diagnostic value for advanced fibrosis as well as cirrhosis. Furthermore, there is also a gradual increase in GP73 expression with disease progression from mild fibrosis to cirrhosis. In conclusion, GP73 is an effective and reliable serological marker for the diagnosis of advanced fibrosis and prediction of appearance of cirrhosis.

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.

Con: Steroids Should Not Be Withdrawn in Transplant Recipients With Autoimmune Hepatitis

Autoimmune liver diseases (AILDs) can recur following liver transplantation (LT) despite immunosuppressive therapy, with implications for graft survival. Although the evidence is not robust, disease recurrence seems to occur in the presence of less intense and/or steroid-free immunosuppression (IS) in particular in the case of autoimmune hepatitis (AIH). The main risk factor for AIH recurrence is the severity of disease activity in the explant and potential donor/recipient human leukocyte antigen D-related 3 (DR3) mismatch. The treatment for AIH recurrence includes reintroduction or increase in the dose of steroids with or without the addition of azathioprine. T cell-mediated rejection episodes are also more common in AILD. Steroid withdrawal is the common practice in LT for non-AILD, eliminating the risks associated with longterm exposure to steroids. In AILD, maintenance of steroids at a low dose in the long term may reduce the risk of disease recurrence and rejection. This strategy is safe when there is vigilance for steroid-related adverse effects. Alternatively, identifying patients who are at the greatest risk for disease recurrence and who would benefit from intensified IS might be an option.

Acute, Chronic, and Humoral Rejection: Pathologic Features Under Current Immunosuppressive Regimes

Under current immunosuppressive regimes, T-cell-mediated acute and chronic rejection remain common and important posttransplant complications. The definition of humoral (antibody-mediated) rejection has been greatly expanded in recent years. The histopathologic assessment of allograft biopsies continues to serve an important role in the diagnosis of rejection and to facilitate patient management. The diagnosis of both acute and chronic antibody-mediated rejection requires integration of the results of donor-specific antibody testing and C4d immunostaining, as well as exclusion of other potential etiologies of allograft dysfunction. Chronic antibody-mediated rejection should also be included in the differential diagnosis for unexplained allograft fibrosis.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe liver disease that affects children and adults worldwide. The diagnosis of AIH relies on increased serum transaminase and immunoglobulin G levels, presence of autoantibodies and interface hepatitis on liver histology. AIH arises in genetically predisposed individuals when a trigger, such as exposure to a virus, leads to a T cell-mediated autoimmune response directed against liver autoantigens; this immune response is permitted by inadequate regulatory immune control leading to a loss of tolerance. AIH responds favourably to immunosuppressive treatment, which should be started as soon as the diagnosis is made. Standard regimens include fairly high initial doses of corticosteroids (prednisone or prednisolone), which are tapered gradually as azathioprine is introduced. For those patients who do not respond to standard treatment, second-line drugs should be considered, including mycophenolate mofetil, calcineurin inhibitors, mechanistic target of rapamycin (mTOR) inhibitors and biologic agents, which should be administered only in specialized hepatology centres. Liver transplantation is a life-saving option for those who progress to end-stage liver disease, although AIH can recur or develop de novo after transplantation. In-depth investigation of immune pathways and analysis of changes to the intestinal microbiota should advance our knowledge of the pathogenesis of AIH and lead to novel, tailored and better tolerated therapies.

Neutrophils and neutrophil extracellular traps in the liver and gastrointestinal system

Neutrophil extracellular traps (NETs) have an important role during infection by helping neutrophils to capture and kill pathogens. However, evidence is accumulating that uncontrolled or excessive production of NETs is related to the exacerbation of inflammation and the development of autoimmunity, cancer metastasis and inappropriate thrombosis. In this Review, we focus on the role of NETs in the liver and gastrointestinal system, outlining their protective and pathological effects. The latest mechanistic insights in NET formation, interactions between microorganisms and NETs and the relationship between neutrophil subtypes and their functions are also discussed. Additionally, we describe the potential importance of NET-related molecules, including cell-free DNA and hypercitrullinated histones, as biomarkers and targets for therapeutic intervention in gastrointestinal diseases.

Diagnosis and Management of Pediatric Autoimmune Liver Disease: ESPGHAN Hepatology Committee Position Statement

Paediatric autoimmune liver disease is characterized by inflammatory liver histology, circulating autoantibodies, and increased levels of IgG, in the absence of a known etiology. Three conditions have a likely autoimmune pathogenesis: autoimmune hepatitis (AIH), autoimmune sclerosing cholangitis, and de novo AIH after liver transplantation. Two types of pediatric AIH are recognized according to seropositivity for smooth muscle and/or antinuclear antibody (AIH-1) or liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibodies (AIH-2).Pertinent issues addressing the diagnosis, treatment, and long-term follow-up were formulated by a core group of ESPGHAN members. They have commissioned the first authors with execution of this project. Initially, they have performed a systematic literature search on MEDLINE, ResearchGate, and Mendeley databases during the last 30 years and produced a document focusing on prospective and retrospective studies in children. The ESPGHAN core group and ESPGHAN Hepatology Committee members voted on each recommendation, using a formal voting technique.

Autoantibodies against CYP-2C19: A Novel Serum Marker in Pediatric De Novo Autoimmune Hepatitis?

Diagnosis of de novo autoimmune hepatitis (AIH) after orthotopic liver transplantation (OLT) is challenging especially in the absence of hyper-γ-globulinemia. Circulating autoantibodies are not sensitive nor specific in de novo AIH but when positive increase the diagnostic probability. We report the discovery of novel liver microsomal (LM) autoantibodies against CYP-2C19 in a 9-year-old boy with “de novo” AIH developed 7 years after OLT. Graft dysfunction presented with hypertransaminasemia (up to 400 IU/L), while serum γ-globulins remained within the normal range for age. Liver histology and response to high dose prednisone (2 mg/kg/day) with the addition of azathioprine therapy further supported the diagnosis of de novo AIH. Autoantibodies investigation by indirect immunofluorescence (IF) on rodent tissues showed a novel staining pattern involving the pericentral liver zone and sparing the renal tissue. Human but not rat liver proteins immunoblotting allowed us to characterize the novel LM antibodies and to identify CYP-2C19 as human antigen. The finding offers insights into the controversial discussion about autoimmunity versus alloreactivity with regard to the pathogenesis of de novo AIH. Correct information on human versus rat tissue antigens tested by methods other than IF for antibodies detection may have significant implications for the correct diagnosis and management of patients followed up after OLT.

Outcomes of Liver Transplant Recipients With Autoimmune Liver Disease Using Long-Term Dual Immunosuppression Regimen Without Corticosteroid

Background

Liver transplant (LT) recipients with autoimmune liver disease (primary sclerosing cholangitis, primary biliary cholangitis, autoimmune hepatitis) are at increased risk of developing acute cellular rejection (ACR), and in many cases graft failure due to recurrent disease. We describe our experience with dual immunosuppression without steroid maintenance and analyze its effect on disease recurrence; ACR; patient and graft survivals; and complications, such as sepsis and de novo malignancy.

Methods

We included 74 consecutive LT recipients (April 2006 to April 2013) with autoimmune liver disease (primary sclerosing cholangitis, 20; primary biliary cholangitis, 23; autoimmune hepatitis, 31) from a single transplant center. Immunosuppression protocol included rabbit antithymocyte globulin for induction and mycophenolate mofetil with tacrolimus or sirolimus/everolimus indefinitely for maintenance.

Results

Overall 1-, 3-, 5-, and 7-year patient survival was 95.9%, 90.4%, 82,2% and 74.9%, re–graft-free survival was 93.2%, 86.3%, 79.9%, and 72.8%, respectively (median follow-up, 5.5 years). In a multivariate Cox regression analysis, sepsis during post-LT period (P = 0.040; hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.04-6.11), steroid use for ACR (P = 0.037; HR, 2.60; 95% CI, 1.06-6.34), and younger age (<40 years) at LT (P = 0.038; HR, 2.53; 95% CI, 1.05-6.10) predicted graft survival, whereas steroid use for ACR was the only variable that was predictive of overall patient survival (P = 0.004; HR, 4.10; 95% CI, 1.59-10.52). Overall, 34 biopsy-proven ACR was noted in 22 LT recipients (30%), 13 (17.5%) had disease recurrence, and 34 episodes of sepsis occurred in 19 patients.

Conclusions

Dual immunosuppression protocol in LT recipients with autoimmune liver disease without corticosteroid maintenance had acceptable rates of survival and ACR without predisposing patients to the adverse effects of long-term steroid therapy.

Autoimmune Hepatitis in the Liver Transplant Graft

Recurrent autoimmune hepatitis (AIH) and de novo AIH are 2 important causes of late graft failure after liver transplantation (LT). Recurrent AIH occurs in patients who undergo LT for AIH. De novo AIH occurs in patients who are transplanted for etiologies other than AIH. Although typically treated with standard treatment for AIH, including corticosteroids and azathioprine, both recurrent and de novo AIH may progress to end-stage liver disease requiring retransplantation.

Recurrence of primary sclerosing cholangitis, primary biliary cholangitis and auto-immune hepatitis after liver transplantation

Liver transplantation is a well-accepted treatment for decompensated chronic liver disease due to primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and auto-immune hepatitis (AIH). Survival after liver transplantation is generally good with 1 and 5-year survival rates around 90% and 70-85%. After transplantation, however, these diseases recur in 8.6-27% (rPSC), 10.9-42.3% (rPBC) and 7-42% (rAIH), and this poses significant challenges in terms of management and graft outcome in these patients. In this review we discuss the incidence, clinical presentation, challenges in diagnosis, reported risk factors and impact on post-transplant outcomes of recurrence of PSC, PBC and AIH after liver transplantation. We also discuss some of the limitations of current investigations and formulate idea's for future research objectives.

2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

Cutting edge issues in autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe liver disease affecting all age groups worldwide. Novel basic and clinical aspects of AIH, addressed at a Monothematic Conference in London in September 2015, are highlighted in this review. The diagnosis of AIH relies upon detection of characteristic autoantibodies, hypergammaglobulinemia, and interface hepatitis on liver histology. The International Autoimmune Hepatitis Group (IAIHG) has devised diagnostic scoring systems to help in comparative studies and clinical practice. AIH arises in a genetically predisposed host, when yet unknown triggers - such an encounter with a pathogen - lead to a T cell-mediated immune response targeting liver autoantigens. This immune response is inadequately controlled because regulatory mechanisms are impaired. The mainstay of treatment for AIH is immunosuppression, which should be instituted as soon as the diagnosis is made. Standard treatment regimens include relatively high doses of predniso(lo)ne, which are tapered gradually as azathioprine is introduced. Recent guidelines have described newer treatment regimens and have tightened the goal of therapy to complete normalization of biochemical, serological and histological parameters. Mycophenolate mofetil, calcineurin inhibitors, mTOR inhibitors and biological agents are potential salvage therapies, but should be reserved for selected non-responsive patients and administered only in experienced centers. Liver transplantation is a life-saving option for those patients who progress to end-stage liver disease. Further dissection of cellular and molecular pathways involved in AIH pathogenesis is likely to lead to the discovery of novel, tailored and better tolerated therapies.

The Zika outbreak of the 21st century

The Zika virus outbreak has captivated the attention of the global audience and information has spread rapidly and wildly through the internet and other media channels. This virus was first identified in 1947, when it was isolated from a sentinel rhesus monkey placed by British scientists working at the Yellow Fever Research Laboratory located in the Zika forest area of Uganda, hence its name, and is transmitted primarily by the mosquito vector, Aedes aegypti. The fact that the rhesus macaque is an Asian species being placed in an African forest brings to mind the possibility of rapid adaptation of the virus from an African to Asian species, an issue that has not been considered. Whether such adaptation has played any role in acquiring pathogenicity due to cross species transmission remains to be identified. The first human infection was described in Nigeria in 1954, with only scattered reports of about a dozen human infections identified over a 50-year period. It was not until 2007 that Zika virus raised its ugly head with infections noted in three-quarters of the population on the tiny island of Yap located between the Philippines and Papua New Guinea in the western Pacific Ocean, followed by a major outbreak in French Polynesia in 2013. The virus remained confined to a narrow equatorial band in Africa and Asia until 2014 when it began to spread eastward, first toward Oceania and then to South America. Since then, millions of infected individuals have been identified in Brazil, Colombia, Venezuela, including 25 additional countries in the Americas. While the symptoms associated with Zika virus infection are generally mild, consisting of fever, maculopapular rash, arthralgia and conjunctivitis, there have been reports of more severe reactions that are associated with neurological complications. In pregnant women, fetal neurological complications include brain damage and microcephaly, while in adults there have been several cases of virus-associated Guillain-Barre syndrome. The virus was until recently believed to only be transmitted via mosquitoes. But when the Zika virus was isolated from the semen specimens from a patient in Texas, this provided the basis for the recent report of possible sexual transmission of the Zika virus. Due to the neurological complications, various vectors for infection as well as the rapid spread throughout the globe, it has prompted the World Health Organization to issue a global health emergency. Various governmental organizations have recommended that pregnant women do not travel to countries where the virus is epidemic, and within the countries affected by the virus, recommendations were provided for women of childbearing age to delay pregnancy. The overall public health impact of these above findings highlights the need for a rapid but specific diagnostic test for blood banks worldwide to identify those infected and for the counseling of women who are pregnant or contemplating pregnancy. As of this date, there are neither commercially licensed diagnostic tests nor a vaccine. Because cross-reactivity of the Zika virus with dengue and Chikungunya virus is common, it may pose difficulty in being able to quickly develop such tests and vaccines. So far the most effective public health measures include controlling the mosquito populations via insecticides and preventing humans from direct exposure to mosquitoes.