De novo autoimmune hepatitis –is this different in adults compared to children?

Autoimmune Hepatitis: A Diagnostic and Therapeutic Overview

Autoimmune hepatitis is an immune-mediated inflammatory condition of the liver of undetermined cause that affects both sexes, all ages, races, and ethnicities. Its clinical presentation can be very broad, from having an asymptomatic and silent course to presenting as acute hepatitis, cirrhosis, and acute liver failure potentially requiring liver transplantation. The diagnosis is based on histological abnormalities (interface hepatitis), characteristic clinical and laboratory findings (increased aspartate aminotransferase, alanine aminotransferase, and serum IgG concentration), and the presence of one or more characteristic autoantibodies. The large heterogeneity of these clinical, biochemical, and histological findings can sometimes make a timely and proper diagnosis a difficult task. Treatment seeks to achieve remission of the disease and prevent further progression of liver disease. First-line therapy includes high-dose corticosteroids, which are later tapered to decrease side effects, and azathioprine. In the presence of azathioprine intolerance or a poor response to the standard of care, second-line therapy needs to be considered, including mycophenolate mofetil. AIH remains a diagnostic and therapeutic challenge, and a further understanding of the pathophysiological pathways of the disease and the implementation of randomized controlled trials are needed.

A variety of death modes of neutrophils and their role in the etiology of autoimmune diseases

Neutrophils are important in the context of innate immunity and actively contribute to the progression of diverse autoimmune disorders. Distinct death mechanisms of neutrophils may exhibit specific and pivotal roles in autoimmune diseases and disease pathogenesis through the orchestration of immune homeostasis, the facilitation of autoantibody production, the induction of tissue and organ damage, and the incitement of pathological alterations. In recent years, more studies have provided in-depth examination of various neutrophil death modes, revealing nuances that challenge conventional understanding and underscoring their potential clinical utility in diagnosis and treatment. This review explores the multifaceted processes and characteristics of neutrophil death, with a focus on tailored investigations within various autoimmune diseases. It also highlights the potential interplay between neutrophil death and the landscape of autoimmune disorders. The review encapsulates the pertinent pathways implicated in various neutrophil death mechanisms across diverse autoimmune diseases while also charts possible avenues for future research.

A review of histopathologic features of pediatric autoimmune liver disease

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Epigenetics in inflammatory liver diseases: A clinical perspective (Review)

Inflammatory liver diseases are, nowadays, multifactorial and wide-spread, thus having an important socio-economic impact. Although the therapeutic algorithms are well-known in hepatitis, regardless of etiology, strategies to identify inflammatory hepatic lesions in early stages and to develop new epigenetic therapies should be prioritized. The main entities of inflammatory liver disease are: alcoholic and non-alcoholic fatty liver disease, autoimmune hepatitis, viral hepatitis and Wilson disease. The main epigenetic processes include: DNA methylation/demethylation, which imply changes in DNA tertiary structure; post-translational histone covalent changes (methylation/demethylation, acetylation/deacetylation, ubiquitination), that cause DNA-histone instability; synthesis of small, non-coding RNA molecules, called microRNAs, that modulate translational potential of transcripts (mRNAs) and post-translational modification of polypeptide chains. Consequently, the epigenetic interactions aforementioned, play an important modulatory role in disease progression and response to conventional therapies The present review focused on the main epigenetic changes in inflammatory liver conditions, considering a new perspective: Epigenetic therapy. This approach is more than welcomed, taking into consideration that conventional therapeutic strategies are almost exhausted.

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.

Peptides of H. sapiens and P. falciparum that are predicted to bind strongly to HLA-A*24:02 and homologous to a SARS-CoV-2 peptide

AIM

This study is looking for a common pathogenicity between SARS-CoV-2 and Plasmodium species, in individuals with certain HLA serotypes.

METHODS

1. Tblastx searches of SARS-CoV-2 are performed by limiting searches to five Plasmodium species that infect humans. 2. Aligned sequences in the respective organisms' proteomes are searched with blastp. 3. Binding predictions of the identified SARS-CoV-2 peptide to HLA supertype representatives are performed. 4. Blastp searches of predicted epitopes that bind strongly to the identified HLA allele are performed by limiting searches to H. sapiens and Plasmodium species, separately. 5. Peptides with minimum 60% identity to the predicted epitopes are found in results. 6. Peptides among those, which bind strongly to the same HLA allele, are predicted. 7. Step-4 is repeated by limiting searches to H. sapiens, followed by the remaining steps until step-7, for peptides sourced by Plasmodium species after step-6.

RESULTS

SARS-CoV-2 peptide with single letter amino acid code CFLGYFCTCYFGLFC has the highest identity to P. vivax. Its YFCTCYFGLF part is predicted to bind strongly to HLA-A*24:02. Peptides in the human proteome both homologous to YFCTCYFGLF and with a strong binding affinity to HLA-A*24:02 are YYCARRFGLF, YYCHCPFGVF, and YYCQQYFFLF. Such peptides in the Plasmodium species' proteomes are FFYTFYFELF, YFVACLFILF, and YFPTITFHLF. The first one belonging to P. falciparum has a homologous peptide (YFYLFSLELF) in the human proteome, which also has a strong binding affinity to the same HLA allele.

CONCLUSION

Immune responses to the identified-peptides with similar sequences and strong binding affinities to HLA-A*24:02 can be related to autoimmune response risk in individuals with HLA-A*24:02 serotypes, upon getting infected with SARS-CoV-2 or P. falciparum.

Pathogenesis of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic progressive liver disease whose etiology and pathogenesis are not yet clear. It is currently believed that the occurrence of AIH is closely related to genetic susceptibility and immune abnormalities, and other factors such as environment, viral infection and drugs that may cause immune dysfunction. This article reviews the pathogenesis of AIH and describes the latest research results in the past 5 years.

A two decade long study of disease progression of de novo and recurrent autoimmune hepatitis in the pediatric population

Recurrent autoimmune hepatitis (rAIH) occurs in patients who undergo liver transplantation (LT) for AIH and de novo AIH (dAIH) is seen in patients who are transplanted for etiologies other than AIH. Whether these are distinct diseases with a similar phenotype remains understudied. The aim of this study was to identify clinical and immunologic factors affecting outcome in patients with dAIH and rAIH. A retrospective review of 387 LT patients from 1997 to 2014 was carried out, and they were followed until 2018. Patients with rAIH or dAIH were identified based on the pre-transplant diagnosis of AIH (or not) and characteristic histology. Liver biopsies were stained with H&E, B-cell marker CD20, and plasma cell marker CD138. Out of 387 patients, 31 were transplanted for AIH, and 8/31 developed rAIH. Of the remaining 356 patients, eight developed dAIH. Compared to the dAIH group, rAIH occurred in older patients, had an earlier onset in the allograft, and had higher IgG and serum ALT levels. It was most commonly seen in African American (AA) patients (87%). rAIH patients had significantly higher CD20 and CD138 positivity in liver biopsies. In addition, they had increased rejection episodes prior to the onset of recurrence, increased graft loss, and mortality. rAIH is a more aggressive disease, and has a preponderance of B cells and plasma cells in the liver tissue as compared to dAIH. The concurrent association with increased graft loss and patient mortality in rAIH warrants further investigations into B cell-targeted therapies.

Autoantibodies and Donor-specific Antibodies are Associated With Graft Dysfunction in Pediatric Liver Transplantation

OBJECTIVES

Autoantibodies (AAb) and donor-specific HLA antibodies (DSA) are frequently present in pediatric liver transplant (LT) recipients. Their clinical significance remains incompletely understood. We aimed to investigate the prevalence of serum AAb and DSA in pediatric LT recipients and its correlation with patient characteristics and histological and biochemical parameters.

METHODS

We retrospectively reviewed the data from 62 pediatric LT patients in follow-up at Ghent University Hospital between January 2007 and February 2018. Blood samples with AAb measurement were taken systematically, liver biopsies (LB) were performed on clinical indication.

RESULTS

AAb were detected in 27 (43.3%) patients, with antinuclear antibodies (ANA) being the most frequently (24%) encountered AAb. There was an association between AAb positivity and female gender (P = 0,032) and deceased donor LT (P = 0,006). Patients with positive AAb underwent a higher number of LB during their follow-up (P < 0,001), and an association was found with the presence of nonspecific histologic alterations (P = 0,032) in the absence of de novo autoimmune hepatitis. Positive AAb were also associated with higher alkaline phosphatase (P < 0,001), ALT (P < 0,001), AST (P < 0,001), γ-GT (P = 0,001), IgG (P = 0,011) and lower albumin (P = 0,029). Fourteen out of 50 (28%) patients were DSA-positive, mostly anti-HLA class II. DSA positivity was associated with T-cell-mediated rejection (P = 0,019), higher total (P = 0,033), and direct (P = 0,012) bilirubin and γ-GT (P < 0,001).

CONCLUSIONS

The presence of AAb and DSA is associated with histological and biochemical parameters of graft dysfunction. Larger prospective studies are warranted to investigate the causal relationships between AAb and DSA development and outcome parameters post pediatric LT.

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.

[Autoimmune liver diseases]

Autoimmune liver diseases comprise a spectrum of progredient idiopathic inflammatory diseases. Typical histological features of autoimmune hepatitis (AIH) include the pattern of chronic hepatitis with predominant plasma cell-rich interface activity, rosetting of hepatocytes, and emperipolesis. Florid bile duct lesions are the key feature of primary biliary cholangitis (PBC); onion-like periductal fibrosis characterizes the primary sclerosing cholangitis (PSC). Variants of AIH, or overlap syndromes, show intersecting histomorphologic findings with PBC or PSC. The diagnosis of the different autoimmune inflammatory liver diseases is based on clinical presentation, a hepatitic or cholestatic pattern of liver enzymes, immuno-serological findings, image analysis in PSC, and liver biopsy as a facultative or obligatory adjunct. Liver biopsy plays a major role in the diagnosis of AIH, small-duct PSC, AMA-negative PBC, IgG4-related diseases, overlap syndrome, and in the recognition of concurrent liver diseases, especially drug-induced liver diseases. Herewith pathologists can help clinicians find adequate therapy for different autoimmune inflammatory liver diseases.

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.

The use of biologics in the treatment of autoimmune liver disease

Introduction: Autoimmune liver diseases include autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and juvenile autoimmune hepatitis (JAIH). The pathophysiologic features of each disease vary, but generally include presence of autoantibodies, cytokine abnormalities, and/or T and B cell autoreactivity.Areas covered: This article compares conventional therapy with newer biologics available for treatment of autoimmune liver diseases. Conventional therapy involves the use of immunosuppressive agents, or other treatment modalities for specific autoimmune liver diseases such as ursodeoxycholic acid and fibrates for PBC. Biologics were developed to target the production of autoantibodies by B cells, the presence of proinflammatory cytokines, adhesion molecules or T and B cell activation.Expert opinion: Despite the promise of biologics being able to target specific cellular and humoral pathways, results have been generally poor, and safety has not been as expected. Cases of autoimmune hepatitis have also developed with the use of these biologicals. Reasons for the lack of success of biologics in treating autoimmune liver disease has led to a reevaluation of our understanding of underlying pathogenesis, demonstrating that while our knowledge of the immunity has improved over the past two decades, it is far from complete.

Bystander activation and autoimmunity

The interaction over time of genetic, epigenetic and environmental factors (i.e., autoimmune ecology) increases or decreases the liability an individual would have to develop an autoimmune disease (AD) depending on the misbalance between risk and protective effects. Pathogens have been the most common antecedent events studied, but multiple other environmental factors including xenobiotic chemicals, drugs, vaccines, and nutritional factors have been implicated into the development of ADs. Three main mechanisms have been offered to explain the development of autoimmunity: molecular mimicry, epitope spreading, and bystander activation. The latter is characterized by auto-reactive B and T cells that undergo activation in an antigen-independent manner, influencing the development and course of autoimmunity. Activation occurs due to a combination of an inflammatory milieu, co-signaling ligands, and interactions with neighboring cells. In this review, we will discuss the studies performed seeking to define the role of bystander activation in systemic and organ-specific ADs. In all cases, we are cognizant of individual differences between hosts and the variable latency time for clinical expression of disease, all of which have made our understanding of the etiology of loss of immune tolerance difficult and enigmatic.