Pathogenesis of autoimmune hepatitis

Breakdown in hepatic tolerance and its relation to autoimmune liver diseases

The liver is a complex immunological organ. It has both immunogenic and tolerogenic capacity. Tolerogenic potential of human liver with its protective firewalls is required to guard the body against the continuous influx of microbial product from the gut via the sinusoids and biliary tree. Immunotolerance and anergic state is maintained by a combined effort of both immune cells, parenchyma cells, epithelial and endothelial cells. Despite this, an unknown trigger can ignite the pathway towards breakdown in hepatic tolerance leading to autoimmune liver diseases. Understanding the initial stimulus which causes the hepatic immune system to switch from the regulatory arm towards self-reactive effector arm remains challenging. Dissecting this pathology using the current technological advances is crucial to develop curative immune based therapy in autoimmune liver diseases. We discuss the hepatic immune cells and non-immune cells which maintain liver tolerance and the evidence of immune system barrier breach which leads to autoimmune hepatitis, primary biliary cholangitis and primary sclerosing cholangitis.

Antisense oligonucleotide is a promising intervention for liver diseases

As the body's critical metabolic organ, the liver plays an essential role in maintaining proper body homeostasis. However, as people's living standards have improved and the number of unhealthy lifestyles has increased, the liver has become overburdened. These have made liver disease one of the leading causes of death worldwide. Under the influence of adverse factors, liver disease progresses from simple steatosis to hepatitis, to liver fibrosis, and finally to cirrhosis and cancer, followed by increased mortality. Until now, there has been a lack of accepted effective treatments for liver disease. Based on current research, antisense oligonucleotide (ASO), as an alternative intervention for liver diseases, is expected to be an effective treatment due to its high efficiency, low toxicity, low dosage, strong specificity, and additional positive characteristics. In this review, we will first introduce the design, modification, delivery, and the mechanisms of ASO, and then summarize the application of ASO in liver disease treatment, including in non-alcoholic fatty liver disease (NAFLD), hepatitis, liver fibrosis, and liver cancer. Finally, we discuss challenges and perspectives on the transfer of ASO drugs into clinical use. This review provides a current and comprehensive understanding of the integrative and systematic functions of ASO for its use in liver disease.

Vaccine-Related Autoimmune Hepatitis: Emerging Association with SARS-CoV-2 Vaccination or Coincidence?

BACKGROUND

There is an increasing number of liver injury cases resembling autoimmune hepatitis (AIH) following SARS-CoV-2 vaccination; however, an association has not yet been established.

METHODS/MATERIALS

A literature review was performed to identify articles regarding the association of AIH with vaccination, emphasizing on SARS-CoV-2 vaccines, and the proposed mechanisms. We then performed a literature search for AIH-like cases following SARS-CoV-2 vaccination, and we evaluated the included cases for AIH diagnosis using simplified diagnostic criteria (SDC), and for vaccination causality using the Naranjo score for adverse drug reactions.

RESULTS

We identified 51 AIH-like cases following SARS-CoV-2 vaccination. Forty cases (80%) were characterized as "probable", "at least probable", or "definite" for AIH diagnosis according to SDC. Forty cases (78.4%) were characterized as "probable", four (7.8%) as "possible", and three (5.8%) as "definite" for vaccine-related AIH according to the Naranjo score.

CONCLUSION

SARS-CoV-2 vaccine-related AIH carries several phenotypes and, although most cases resolve, immunosuppressive therapy seems to be necessary. Early diagnosis is mandatory and should be considered in any patient with acute or chronic hepatitis after SARS-CoV-2 vaccination, especially in those with pre-existing liver disease.

The association between juvenile autoimmune hepatitis and HLA-DRB1 alleles: Iraqi tertiary center experience

Aim of the study

To highlight the impact of the human leukocyte antigen (HLA) allele on susceptibility and prevention of autoimmune hepatitis (AIH) in Iraqi children.

Material and methods

We conducted a prospective study from children attending the Gastroenterology and Hepatology Clinic of Children’s Welfare Teaching Hospital over five years from the first of September 2015 to the thirty-first of August 2020. It included 19 patients with AIH; their age (at time of diagnosis) ranged between 3 and 16 years, with a female predominance of 78.9%. The diagnosis was made by clinical, serological, and histological features. In addition, 20 age- and sex-matched unrelated subjects of the same ethnic background were selected randomly from healthy individuals undergoing checkup as controls.

Results

19 patients diagnosed with AIH were included in this study, and 20 age- and sex-matched healthy controls, with a female predominance of 78.9%. The commonest autoantibodies found were smooth muscle antibody (SMA) in 13 (68.4%), antinuclear antibody (ANA) in 11 (57.9%). In AIH type 1, PCR showed higher frequencies among patients with HLA-DRB1*03, HLA-DRB1*04, HLA-DRB1*13 alleles in patients with AIH; moreover DRB1*11 and DRB1*15 were less frequent than in the control group. Frequency of HLA-DRB1*04 was 28% and HLA-DRB1*13 was 20% in AIH type 2 patients; HLA-DRB1*13 and HLA-DRB5 showed frequency of 25% for both and HLA-DRB4 frequency was 18.7%.

Conclusions

HLA-DRB1*13, DRB1*04, and DRB1*03 are susceptibility alleles for the development of AIH type 1, while HLA-DRB1*13, HLA-DRB4 and DRB5 are susceptibility alleles for the development of AIH type 2 in Iraqi children.

Autoimmune Hepatitis: Treatment Options and Management Review

Autoimmune hepatitis (AIH) is an inflammatory pathology of the liver which leads to liver cirrhosis and death if left untreated and affects a large population across the world with no ethnic discrimination. AIH can be asymptomatic or with non-typical clinical presentation. The diagnosis and categorization of AIH are based on the presence of autoantibodies, specific biochemical indices, and histopathological features. The categorization of AIH further supports therapeutic management decisions. Associated comorbidities are another worrisome in treatment decisions and better outcomes. Liver transplantation is the ultimate choice in case of zero or minimal therapeutic response or severe liver damage. Liver transplantation also has its associated risks and rejection concerns.

The international guidelines are designed to provide a complete management outline of AIH for better patient management. There is a disparity seen in these guidelines, especially in terms of dose recommendation. This review designed to lay out an overview of the new guidelines on the diagnosis and management of AIH.

Case Report: Acute Hepatitis E in a Pediatric Traveler Presenting with Features of Autoimmune Hepatitis: A Diagnostic and Therapeutic Challenge

Hepatitis E virus (HEV) is globally the most common cause of acute viral hepatitis. In industrialized countries, HEV infection can be seen in travelers returning from hyperendemic countries or in individuals at risk for autochthonous infection due to zoonotic exposure. Hepatitis E virus infection is often unrecognized and at times misdiagnosed because of nonspecific findings that can overlap with other causes of hepatitis, including autoimmune hepatitis (AIH). Although most cases of acute HEV infection resolve spontaneously and do not require treatment, life-threatening acute liver failure may occur in some cases. We discuss the case of an 8-year-old boy returning from Bangladesh with progressive acute liver injury and a clinical profile suggestive of AIH, who showed a favorable response to corticosteroid treatment before the diagnosis of an acute HEV infection could be established.

Fumarate hydratase-specific T cell response in Chinese patients with autoimmune hepatitis

PURPOSE

Fumarate hydratase (FH) is expressed in the serum of patients with autoimmune hepatitis (AIH). The specific involvement of FH-specific T cell response is currently unknown. The aim of the study was to assess the frequency and clinical significance of FH-specific T cell response in AIH.

METHODS

This was a prospective study of 42 consecutive patients admitted to the clinical study center of autoimmune liver disease of our Hospital, Capital Medical University (China) between January 2011 and December 2014. PBMCs were collected and the FH-specific T cell response was detected by Elispot. Cytokines and antibody responses were assessed.

RESULTS

Among the 42 AIH patients, 57.1% showed a positive response to FH peptides. The difference in FH-specific T cell response frequency among AIH patients and control groups was significant (P<0.001). The FH peptides induced the secretion of CD4+ and CD8+ T cells. The FH-specific T cell response in patients with active disease was stronger than in those with remission (P=0.0283). FH-specific T cell response in patients with active disease showed a positive association with ALT (r=0.4712, P=0.0098) and AST (r=0.3924, P=0.0352) levels. The magnitude of the FH-specific T cell response correlated with the HAI score (r=0.7290, P=0.0047) and anti-FH titer (r=0.6457, P=0.0093).

CONCLUSION

FH-specific T cell response may be detected in the blood of patients with AIH and seems to be associated with AIH disease progression. FH-specific T cell response could be a pathogenic cause of AIH.

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.

Natural History and Treatment Outcomes of Severe Autoimmune Hepatitis

GOALS

The aim of this study was to analyze the natural history and treatment outcomes of autoimmune hepatitis (AIH) variants presenting with severe-AIH.

BACKGROUND

Severe acute presentation is an uncommon manifestation of AIH, and it remains poorly characterized.

MATERIALS AND METHODS

We included 101 patients with AIH from January 2011 to December 2015. Patients were classified as seropositive-AIH and seronegative-AIH. Patients with acute liver failure, acute-on-chronic liver failure, and severe acute hepatitis were defined as severe-AIH patients. Patient characteristics and treatment outcomes with follow-up until 12 months were analyzed between the different groups.

RESULTS

Out of 101 cases, 24 (23.76%) had severe AIH. Of them 9 (37.5%) had severe acute hepatitis, 3 (12.5%) had acute liver failure, and 12 (50%) had acute-on-chronic liver failure. Seronegative-AIH patients presented with severe-AIH significantly more frequently compared with seropositive-AIH patients (50% vs. 20.27%, P=0.022). Severe-AIH had 50% complete responders, 25% partial responders, and 25% treatment failures. Jaundice (88.88% vs. 68.7%, P=0.048), encephalopathy (55.55% vs. 6.66%, P=0.014), and higher international normalized ratio values (2.17±0.60 vs. 1.82±0.14, P=0.038) were factors associated with nonresponse rather than the presence or absence of autoantibodies in severe-AIH. The hazard ratio for predicting remission in the non-severe AIH group as compared with the severe-AIH group was 1.502, which was statistically not significant (95% CI, 0.799-2.827; P=0.205).

CONCLUSION

Approximately 24% of patients with AIH have severe-AIH. Conventional autoantibodies are often absent in severe-AIH; however, it does not alter the outcome. Immunosuppressants should be given expediently in patients with severe-AIH.

Innumerable Liver Masses in a Patient with Autoimmune Hepatitis and Primary Sclerosing Cholangitis Overlap Syndrome

BACKGROUND In patients with the diagnosis of autoimmune hepatitis (AIH), the presence of cholestatic features raise the possibility of an overlap syndrome with primary sclerosing cholangitis (PSC). Here, we present a unique case with AIH-PSC overlap syndrome and innumerable liver masses. CASE REPORT A 26-year-old man presented with generalized icterus. Based on the serological findings of hypergamainmunoglobulinemia and positive anti-nuclear antibody tests, together with an abnormal cholangiogram, he was diagnosed with overlap syndrome (AIH-PSC). Liver imaging revealed innumerable liver masses with a benign appearance in the pathological evaluation. To rule out the colon abnormalities that usually coexist with such liver masses, colonoscopy was performed and showed no significant changes. The liver masses were nonmalignant and were resolved after immunosuppressant therapy. CONCLUSIONS Because AIH-PSC overlap syndrome is rare, it is suggested that radiological evaluation of the biliary tree should be performed routinely in adults diagnosed with AIH to reduce the missed diagnosis of overlap syndrome and liver masses.

Celecoxib attenuates depressive-like behavior associated with immunological liver injury in C57BL/6 mice through TNF-α and NF-κb dependent mechanisms

AIM

Depression associating patients with chronic liver diseases is a major treatment goal. This study aimed to evaluate the potential hepatoprotective and antidepressant effects of celecoxib in a model of experimental autoimmune hepatitis (EAH) and depressive-like behavior in C57BL/6 mice.

MAIN METHODS

EAH was induced by immunization with S-100 liver antigen emulsified in complete Freund's adjuvant (CFA). Mice were randomly allocated to 5 groups; control phosphate buffered saline group; control CFA group; EAH group, and 2 groups of EAH plus celecoxib (7.5 or 15mg/kg/d respectively). Mice were assessed behaviorally by novelty-suppressed test, tail suspension test, locomotor assessment and forced swimming tests. Serum liver enzymes and hepatic hydroxyproline content were biochemically analyzed. Histopathological analysis for liver and brain sections and immunohistochemical studies for hepatic and hippocampal tumor necrosis factor (TNF-α), nuclear factor Kappa-B (NF-κB) and caspase-3 were performed.

KEY FINDINGS

EAH group exhibited significant depressive-like changes, increase in liver enzymes and hepatic hydroxyproline content. Signs of autoimmune hepatitis and structural changes in hippocampus were confirmed by histopathological studies. Immunohistochemical examination revealed overexpression of hepatic and hippocampal TNF-α, NF-κB and caspase-3 positive cells. Celecoxib (7.5mg/kg/d) significantly ameliorated hepatic biochemical changes, hepatic and hippocampal histopathological and immunohistochemical changes induced in EAH group. Celecoxib (15mg/kg/d) significantly ameliorated the behavioral changes, histopathological and immunohistochemical changes in hippocampus, with non-significant change in hepatic biochemical profile, histopathological and immunohistochemical changes induced in EAH group.

SIGNIFICANCE

The celecoxib (7.5mg/kg/d) through its anti-inflammatory effect may represent a new therapeutic approach to treat autoimmune hepatitis associated with depressive symptoms.

Alcohol Dehydrogenase: An Autoantibody Target in Patients with Alcoholic Liver Disease

The link between alcohol consumption and liver disease is not direct and several factors including autoimmunity to hepatocyte components have been implicated. We have previously identified alcohol dehydrogenase (ADH) as an autoantigen in autoimmune liver disease and in a proportion of patients with alcoholic liver disease. The aim of the present study is to investigate the association between the presence of anti-ADH antibodies, alcohol consumption and severity of liver damage in alcoholic patients. The presence of antibodies to human ADH β2 and horse ADH was investigated in 108 patients with documented history of alcohol consumption and alcohol related liver disease, 86 being active alcohol abusers and 22 on sustained alcohol withdrawal, 39 with non-alcohol related disease and 22 normal subjects.

Antibodies to either ADH form were more frequently detected in active alcohol abusers (55/86, 64%) than in patients on sustained alcohol withdrawal longer than 6 months (1/8, 13%, p<0.005), HBV infection (2/8, 25%, P=0.03), non-alcohol related disease (9/29, 23%, p<0.0001) and in normal controls (3/22, 14%, p<0.0001); were more frequent in patients with cirrhosis than in those with steatosis (26/34, 76% vs 34/64, 53%, P=0.02); and were associated with elevated levels of ALT (anti-ADH β2, p<0.05), immunoglobulin A (p<0.05) and γ-glutamyl transpeptidase (P=0.01). Anti-ADH antibody positive serum samples were able to inhibit the enzymatic activity of ADH. These findings suggest that anti-ADH antibodies may be triggered by alcohol consumption and act as a disease activity marker in alcoholic liver disease.

Transitioning from Idiopathic to Explainable Autoimmune Hepatitis

Autoimmune hepatitis lacks an identifiable cause, and its diagnosis requires the exclusion of etiologically defined diseases that resemble it. Insights into its pathogenesis are moving autoimmune hepatitis from an idiopathic to explainable disease, and the goal of this review is to describe the insights that are hastening this transition. Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens. DRB1 alleles are the principal susceptibility factors in white adults, and a six amino acid sequence encoded in the antigen-binding groove of class II molecules of the major histocompatibility complex can influence the selection of autoantigens. Polymorphisms, including variants of SH2B3 and CARD10 genes, may affect immune reactivity and disease severity. The cytochrome mono-oxygenase, CYP2D6, is the autoantigen associated with type 2 autoimmune hepatitis, and it shares homologies with multiple viruses that might promote self-intolerance by molecular mimicry. Chemokines, especially CXCL9 and CXCL10, orchestrate the migration of effector cells to sites of injury and are associated with disease severity. Cells of the innate and adaptive immune responses promote tissue damage, and possible deficiencies in the number and function of regulatory T cells may facilitate the injurious process. Receptor-mediated apoptosis is the principal mechanism of hepatocyte loss, and cell-mediated and antibody-dependent mechanisms of cytotoxicity also contribute. Insights that explain autoimmune hepatitis will allow triggering exogenous antigens to be characterized, risk management to be improved, prognostic indices to be refined, and site-specific therapeutic interventions to emerge.

Mycobacteria and autoimmunity

Mycobacterial infections can cause a variety of different manifestations. The increasing incidence of these infections worldwide brought another medical dilemma: immunological manifestations characterized by the presence of many autoantibodies and concomitant presence of autoimmune diseases. The burden of tuberculosis reactivation that emerged with immunosuppressive therapy worsened with the growing use of biological disease-modifying antirheumatic drugs (DMARDs). This review will address the relationship between the immune system and mycobacteria.

Medullary thymic epithelial cells and central tolerance in autoimmune hepatitis development: novel perspective from a new mouse model

Autoimmune hepatitis (AIH) is an immune-mediated disorder that affects the liver parenchyma. Diagnosis usually occurs at the later stages of the disease, complicating efforts towards understanding the causes of disease development. While animal models are useful for studying the etiology of autoimmune disorders, most of the existing animal models of AIH do not recapitulate the chronic course of the human condition. In addition, approaches to mimic AIH-associated liver inflammation have instead led to liver tolerance, consistent with the high tolerogenic capacity of the liver. Recently, we described a new mouse model that exhibited spontaneous and chronic liver inflammation that recapitulated the known histopathological and immunological parameters of AIH. The approach involved liver-extrinsic genetic engineering that interfered with the induction of T-cell tolerance in the thymus, the very process thought to inhibit AIH induction by liver-specific expression of exogenous antigens. The mutation led to depletion of specialized thymic epithelial cells that present self-antigens and eliminate autoreactive T-cells before they exit the thymus. Based on our findings, which are summarized below, we believe that this mouse model represents a relevant experimental tool towards elucidating the cellular and molecular aspects of AIH development and developing novel therapeutic strategies for treating this disease.

Mouse models of liver fibrosis mimic human liver fibrosis of different etiologies

The liver has the amazing capacity to repair itself after injury; however, the same processes that are involved in liver regeneration after acute injury can cause serious consequences during chronic liver injury. In an effort to repair damage, activated hepatic stellate cells trigger a cascade of events that lead to deposition and accumulation of extracellular matrix components causing the progressive replacement of the liver parenchyma by scar tissue, thus resulting in fibrosis. Although fibrosis occurs as a result of many chronic liver diseases, the molecular mechanisms involved depend on the underlying etiology. Since studying liver fibrosis in human subjects is complicated by many factors, mouse models of liver fibrosis that mimic the human conditions fill this void. This review summarizes the general mouse models of liver fibrosis and mouse models that mimic specific human disease conditions that result in liver fibrosis. Additionally, recent progress that has been made in understanding the molecular mechanisms involved in the fibrogenic processes of each of the human disease conditions is highlighted.

Hepatitis mouse models: from acute-to-chronic autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease associated with interface hepatitis, raised plasma liver enzymes, the presence of autoantibodies and regulatory T-cell (Tregs) dysfunction. The clinical course is heterogeneous, manifested by a fulminant or indolent course. Although genetic predisposition is well accepted, the combination with currently undefined environmental factors is crucial for the development of the disease. Progress in the development of reliable animal models provides added understanding of the pathophysiology of AIH, and these will be very useful in evaluating potential therapeutics. It appears that artificially breaking tolerance in the liver is easy. However, maintaining this state of tolerance breakdown, to get chronic hepatitis, is difficult because liver immune homeostasis is strongly regulated by several immune response inhibitory mechanisms. For example, Tregs are crucial regulators in acute and chronic hepatitis, and C57BL/6 mice are most prone to experimental AIH. Immunization of C57BL/6 mice with liver (AIH) autoantigens (CYP2D6/FTCD or IL-4R) and the disturbance of liver regulatory mechanism(s), leading to experimental AIH, are likely to be most representative of human AIH pathology.

Review article: permanent drug withdrawal is desirable and achievable for autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis can be rendered treatment-free, but the difficulty, frequency and risks associated with the pursuit of this outcome are unclear.

AIM

To describe the frequency that autoimmune hepatitis can be rendered treatment-free, identify the features that characterise these patients, examine the pathogenic pathways that may sustain or terminate the disease and indicate management protocols that can obtain this result.

METHODS

Studies cited in Pub Med from 1972-2014 for autoimmune hepatitis, treatment, relapse, remission and outcome were selected.

RESULTS

The frequency of a treatment-free state varies from 19% to 40% in patients observed for ≥3 years after drug withdrawal. Complete laboratory resolution and reversion to normal liver tissue prior to drug withdrawal favours this response. The development of cirrhosis during therapy may increase treatment-dependence. Persistent liver damage and the generation of neo-antigens during the apoptosis of hepatocytes may perpetuate the disease. Genetic and age-related effects on the vigour of the immune response may also contribute. Reversion to normal liver tissue is achieved in only 22% of patients during conventional corticosteroid therapy, and the emerging pharmacological and biological interventions may improve this frequency. A management strategy designed to achieve a treatment-free state accommodates all candidates for this outcome, and it can be modified to a long-term maintenance strategy as warranted by the clinical response.

CONCLUSIONS

Permanent drug withdrawal is a treatment outcome that is desirable and achievable in patients with autoimmune hepatitis. Normalisation of liver tests and liver tissue during treatment enhances this occurrence.

Epigallocatechin-3-gallate (EGCG) attenuates concanavalin A-induced hepatic injury in mice

(-)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenolic compound present in green tea and has been shown to possess anti-inflammatory and anti-oxidative properties. In this study, we investigated the protective effects of EGCG against concanavalin A (ConA)-induced liver injury and the underlying mechanisms. EGCG (5 mg/kg) was administered orally by gavage to mice twice daily for 10 days before an intravenous injection of ConA. We found that EGCG effectively rescued lethality, improved hepatic pathological damage, and decreased serum levels of alanine aminotransaminase (ALT) in ConA-challenged mice. Furthermore, EGCG also significantly prevented the release of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-4, and IL-6 in serum, reduced malondialdehyde (MDA) levels, and restored glutathione (GSH) content and superoxide dismutase (SOD) activity in liver tissues from ConA-challenged mice. Finally, nuclear factor (NF)-κB activation and expression levels of Toll-like receptor (TLR) 2, TLR4 and TLR9 protein in liver tissues were significantly inhibited by EGCG pretreatment. Taken together, our data suggest that EGCG possesses hepatoprotective properties against ConA-induced liver injury through its anti-inflammatory and anti-oxidant actions.

Meta-analysis: diagnostic accuracy of antinuclear antibodies, smooth muscle antibodies and antibodies to a soluble liver antigen/liver pancreas in autoimmune hepatitis

Background

Antinuclear antibodies (ANA), smooth muscle antibodies (SMA) and antibodies to a soluble liver antigen/liver pancreas (anti-SLA/LP) are useful markers that can help clinicians to diagnose and classify autoimmune hepatitis (AIH).

Objectives

To determine whether ANA, SMA and anti-SLA/LP help to accurately diagnose patients with AIH.

Search strategy

The PubMed, CNKI, WANFANG, and SinoMed databases were accessed to retrieve studies published in English and Chinese. Studies published up to October 2013 were reviewed.

Selection criteria

Studies on the diagnostic value of ANA, SMA or anti-SLA/LP in the diagnosis of known or suspected AIH were included.

Data collection and analysis

Two authors evaluated studies independently and rated their methodological quality using quality assessment of diagnostic accuracy studies (QUADAS) tools; relevant data were abstracted. The random-effects method was used to summarize sensitivities, specificities, positive and negative likelihood ratios, and diagnostic odds ratios (DORs) from all 29 studies.

Results

The pooled sensitivity, specificity, positive and negative likelihood ratios, and DOR for ANA were 0.650 (95% confidence interval [CI], 0.619 to 0.680), 0.751 (95%CI, 0.737 to 0.764), 3.030 (95%CI, 2.349 to 3.910), 0.464 (95%CI, 0.356 to 0.604), and 7.380 (95%CI, 4.344 to 12.539), respectively. For SMA, the values were 0.593 (95%CI, 0.564 to 0.621), 0.926 (95%CI, 0.917 to 0.934), 11.740 (95%CI, 7.379 to 18.678), 0.449 (95%CI, 0.367 to 0.549), and 31.553 (95%CI, 17.147 to 58.060), respectively. Finally, for anti-SLA/LP, the values were 0.194 (95%CI, 0.168 to 0.222), 0.989 (95%CI, 0.985 to 0.993), 11.089 (95%CI, 7.601 to 16.177), 0.839 (95%CI, 0.777 to 0.905), and 16.867 (95%CI, 10.956 to 25.967), respectively.

Authors’ conclusions

ANA provided moderate sensitivity and specificity, while SMA gave moderate sensitivity and high specificity, and anti-SLA/LP exhibited low sensitivity and high specificity. All three antibodies were limited by their unsatisfactory sensitivities and lack of consistency.

Tracing environmental markers of autoimmunity: introducing the infectome

We recently introduced the concept of the infectome as a means of studying all infectious factors which contribute to the development of autoimmune disease. It forms the infectious part of the exposome, which collates all environmental factors contributing to the development of disease and studies the sum total of burden which leads to the loss of adaptive mechanisms in the body. These studies complement genome-wide association studies, which establish the genetic predisposition to disease. The infectome is a component which spans the whole life and may begin at the earliest stages right up to the time when the first symptoms manifest, and may thus contribute to the understanding of the pathogenesis of autoimmunity at the prodromal/asymptomatic stages. We provide practical examples and research tools as to how we can investigate disease-specific infectomes, using laboratory approaches employed from projects studying the “immunome” and “microbiome”. It is envisioned that an understanding of the infectome and the environmental factors that affect it will allow for earlier patient-specific intervention by clinicians, through the possible treatment of infectious agents as well as other compounding factors, and hence slowing or preventing disease development.

Clinical Profile and HLA Typing of Autoimmune Hepatitis From Pakistan

BACKGROUND

Human leukocyte antigen (HLA) typing in autoimmune hepatitis (AIH) has been investigated in different populations and ethnic groups, but no such data is available from Pakistan.

OBJECTIVES

The aim of this study was to evaluate the clinical profile of autoimmune hepatitis (AIH), and determine the associated antigens and alleles by performing HLA typing.

PATIENTS AND METHODS

A total of 58 patients, diagnosed and treated as AIH in the last 10 years were reviewed. Diagnosis was based on International AIH Group criteria. Forty one patients underwent liver biopsy. HLA typing was performed in 44 patients and 912 controls by serological method for HLA A and B, and by PCR technique using sequence specific primers for DR alleles.

RESULTS

Of 58 cases, 35 were females (60.3%). The median age was 14.5 (range 4-70 years), and AIH score was 14 (10-22). Thirty-six (62.0%) patients had type 1 AIH, 10 (17.2%) type 2, and the remaining 12 were seronegative with biopsy proven AIH. Forty-nine patients (84.4%) had cirrhosis. Twenty-four (41.4%) patients had ascites at the time of presentation. Among 41 patients who underwent liver biopsy, thirty-two had advance stages III and IV disease, and twenty had severe grade of inflammation. Fifteen patients had other associated autoimmune diseases and one developed hepatocellular carcinoma. HLA A2 (P = 0.036), HLA A9 (23) (P = 0.018), HLA A10 (25) (P = 0.000), HLA A19 (33) (P = 0.000), HLA B15 (63) (P = 0.007), HLA B40 (61) ( P = 0.002), HLA DR6 (P = 0.001) with its subtypes HLA-DRB1*13 (P = 0.032) and HLA-DRB1*14 (p = 0.017) were more prevalent in AIH with statistical significance than controls.

CONCLUSIONS

AIH in our region presents with advanced disease affecting predominantly children and adolescents. There is a genetic association of HLA DR6 along with other alleles and antigens in our patients with AIH.

Liver immunology

The liver is the largest organ in the body and is generally regarded by nonimmunologists as having little or no lymphoid function. However, such is far from accurate. This review highlights the importance of the liver as a lymphoid organ. Firstly, we discuss experimental data surrounding the role of liver as a lymphoid organ. The liver facilitates tolerance rather than immunoreactivity, which protects the host from antigenic overload of dietary components and drugs derived from the gut and it is instrumental to fetal immune tolerance. Loss of liver tolerance leads to autoaggressive phenomena, which if not controlled by regulatory lymphoid populations, may lead to the induction of autoimmune liver diseases. Liver-related lymphoid subpopulations also act as critical antigen-presenting cells. The study of the immunological properties of liver and delineation of the microenvironment of the intrahepatic milieu in normal and diseased livers provides a platform to understand the hierarchy of a series of detrimental events that lead to immune-mediated destruction of the liver and the rejection of liver allografts. The majority of emphasis within this review will be on the normal mononuclear cell composition of the liver. However, within this context, we will discuss selected, but not all, immune-mediated liver disease and attempt to place these data in the context of human autoimmunity.

Rituximab for refractory autoimmune hepatitis: a case report

Auto-immune hepatitis (AIH) is a chronic progressive hepatitis of unknown aetiology whose clinical presentation ranges from asymptomatic to fulminant hepatic failure. Corticosteroids and azathioprine, which are considered standard therapy for AIH, may, however, be associated with treatment failures and toxicities. Among the alternative medications under investigation, rituximab, used to treat successfully various auto-immune disorders, has fewer side effects. We report herein the case of a 68-year-old woman who developed AIH with worsening clinical, laboratory and histological features despite high-dose prednisone. On rituximab, the patient showed rapid and dramatic clinical improvement, suggesting a therapeutic role for this medication in severe AIH. Indeed, prospective controlled studies are needed to assess and validate this role.

Alcohol dehydrogenase-specific T-cell responses are associated with alcohol consumption in patients with alcohol-related cirrhosis

Patients with alcohol-related liver disease (ALD) have antibodies directed to alcohol dehydrogenase (ADH), anti-ADH titers being associated with disease severity and active alcohol consumption. ADH-specific T-cell responses have not been characterized. We aimed to define anti-ADH cellular immune responses and their association with active alcohol consumption and disease severity. Using cultures of peripheral blood mononuclear cells (PBMCs) from 25 patients with alcohol-related cirrhosis (ARC; 12 were actively drinking or abstinent for <6 months, and 13 were abstinent for >6 months) and hepatic mononuclear cells (HMCs) from 14 patients with ARC who were undergoing transplantation, we investigated T-cell reactivity to 25 overlapping peptides representing the full human ADH protein (beta 1 subunit). ADH-specific peripheral T-cell responses were assessed by the quantification of T-cell proliferation and cytokine production and were correlated with the clinical course. In active alcohol consumers, proliferative T-cell responses targeted ADH31-95 and other discontinuous sequences in the ADH peptide, whereas only one sequence was targeted in abstinents. ADH peptides induced the production of interferon-γ (IFN-γ), interleukin-4 (IL-4), and IL-17. IL-4 production was lower in active drinkers versus abstinents, and IL-17 production was higher. Peptides inducing IFN-γ production outnumbered those inducing T-cell proliferation. The intensity of the predominantly T helper 1 (Th 1) responses directly correlated with disease severity. Similar to PBMCs in abstinents, ADH peptides induced weak T-cell proliferation and a similar level of IL-4 production in HMCs but less vigorous Th 1 and T helper 17 responses.

CONCLUSION

This suggests that Th 1 responses to ADH in ARC are induced by alcohol consumption. A Th 1/T helper 2 imbalance characterizes T-cell responses in active drinkers with ARC, whereas IL-4 production prevails in abstinents. This identifies new targets for immunoregulatory therapies in ALD patients for halting detrimental effector T-cell responses, which may encourage liver fibrogenesis and progression to end-stage liver disease.

Acute and acute severe (fulminant) autoimmune hepatitis

Autoimmune hepatitis frequently has an abrupt onset of symptoms, and it can present with acute liver failure. The abrupt presentation can indicate spontaneous exacerbation of a pre-existent chronic disease, newly created disease, a superimposed infectious or toxic injury, or new disease after viral infection, drug therapy, or liver transplantation. Deficiencies in the classical phenotype may include a low serum immunoglobulin G level and low or absent titers of the conventional autoantibodies. The original revised diagnostic scoring system of the International Autoimmune Hepatitis Group can guide the diagnostic evaluation, but low scores do not preclude the diagnosis. Liver tissue examination is valuable to exclude viral-related or drug-induced liver injury and support the diagnosis by demonstrating centrilobular necrosis (usually with interface hepatitis), lymphoplasmacytic infiltration, hepatocyte rosettes, and fibrosis. Conventional therapy with prednisone and azathioprine induces clinical and laboratory improvement in 68-75 % of patients with acute presentations, and high dose prednisone or prednisolone (preferred drug) is effective in 20-100 % of patients with acute severe (fulminant) presentations. Failure to improve or worsening of any clinical or laboratory feature within 2 weeks of treatment or worsening of a mathematical model of end-stage liver disease within 7 days justifies liver transplantation in acute liver failure. Liver transplantation for acute severe (fulminant) autoimmune hepatitis is as successful as liver transplantation for autoimmune hepatitis with a chronic presentation and other types of acute liver failure (patient survival >1 year, 80-94 %). Liver transplantation should not be delayed or superseded by protracted corticosteroid therapy or the empiric institution of nonstandard medications.

The overlap syndromes of autoimmune hepatitis

Autoimmune hepatitis has two major variant phenotypes in which the features of classical disease are co-mingled with those of primary biliary cirrhosis or primary sclerosing cholangitis. These overlap syndromes lack codified diagnostic criteria, established pathogenic mechanisms, and confident management strategies. Their clinical importance relates mainly to the identification of patients who respond poorly to conventional corticosteroid treatment. Scoring systems that lack discriminative power have been used in their definition, and a clinical phenotype based on pre-defined laboratory and histological findings has not been promulgated. The frequency of overlap with primary biliary cirrhosis is 7-13 %, and the frequency of overlap with primary sclerosing cholangitis is 8-17 %. Patients with autoimmune hepatitis and features of cholestatic disease must be distinguished from patients with cholestatic disease and features of autoimmune hepatitis. Variants of the overlap syndromes include patients with small duct primary sclerosing cholangitis, antimitochondrial antibody-negative primary biliary cirrhosis, autoimmune sclerosing cholangitis, and immunoglobulin G4-associated disease. Conventional corticosteroid therapy alone or in conjunction with ursodeoxycholic acid (13-15 mg/kg daily) has been variably effective, and cyclosporine, mycophenolate mofetil, and budesonide have been beneficial in selected patients. The key cholestatic features that influence the prognosis of autoimmune hepatitis must be defined and incorporated into the definition of the syndrome rather than rely on designations that imply the co-mingling of different diseases with manifestations of variable clinical relevance. The overlap syndromes in autoimmune hepatitis are imprecise, heterogeneous, and unfounded, but they constitute a clinical reality that must be accepted, diagnosed, refined, treated, and studied.

Activated natural killer T cells producing interferon-gamma elicit promoting activity to murine dendritic cell-based autoimmune hepatic inflammation

As natural killer (NK) T cells play an important role in the development of autoimmune diseases, they should have significant roles for the pathogenesis of autoimmune liver disease. Implication of the NK T cells in the generation of autoimmune-related hepatic inflammation was investigated using a novel mouse model. Immunization of mice with dendritic cells (DCs) loaded with hepatocyte-mimicking hepatocellular carcinoma cells (DC/Hepa1-6) induces cytotoxic T lymphocytes (CTL) capable of killing hepatocytes. Subsequent administration of interleukin (IL)-12, a potent interferon-gamma (IFN-γ) inducer, to the immunized mice generates autoimmune hepatic inflammation (AHI), as reported previously. Upon onset of the AHI response, the number of intrahepatic CD3(+) NK1 · 1(+) NK T cells increased markedly, along with a decrease in the number of splenic NK T cells, augmented expression of CXCR6 on intrahepatic NK T cells and CXCL16 in hepatic tissue, suggesting that NK T cells were recruited into the inflamed liver. The NK T cells were strongly positive for CD69 and produced IFN-γ, but not IL-4. AHI activity was attenuated markedly in CD1d(-/-) NK T cell-deficient mice, indicating that NK T cells play a pivotal role in the development of AHI. Mice treated with DC/Hepa1-6 and alpha-galactosylceramide, a potent NK T cell activator, also exhibited similar hepatic inflammation, in which activated NK T cells producing IFN-γ and CD8(+) T cells cytotoxic to hepatocytes were induced in liver-infiltrating mononuclear cells. Activated NK T cells producing IFN-γ potentiate DC-based AHI in the mouse model.

Infectome: a platform to trace infectious triggers of autoimmunity

The "exposome" is a term recently used to describe all environmental factors, both exogenous and endogenous, which we are exposed to in a lifetime. It represents an important tool in the study of autoimmunity, complementing classical immunological research tools and cutting-edge genome wide association studies (GWAS). Recently, environmental wide association studies (EWAS) investigated the effect of environment in the development of diseases. Environmental triggers are largely subdivided into infectious and non-infectious agents. In this review, we introduce the concept of the "infectome", which is the part of the exposome referring to the collection of an individual's exposures to infectious agents. The infectome directly relates to geoepidemiological, serological and molecular evidence of the co-occurrence of several infectious agents associated with autoimmune diseases that may provide hints for the triggering factors responsible for the pathogenesis of autoimmunity. We discuss the implications that the investigation of the infectome may have for the understanding of microbial/host interactions in autoimmune diseases with long, pre-clinical phases. It may also contribute to the concept of the human body as a superorganism where the microbiome is part of the whole organism, as can be seen with mitochondria which existed as microbes prior to becoming organelles in eukaryotic cells of multicellular organisms over time. A similar argument can now be made in regard to normal intestinal flora, living in symbiosis within the host. We also provide practical examples as to how we can characterise and measure the totality of a disease-specific infectome, based on the experimental approaches employed from the "immunome" and "microbiome" projects.

Asialoglycoprotein receptor (ASGPR): a peculiar target of liver-specific autoimmunity

Asialoglycoprotein receptor (ASGPR) autoantibodies have been considered specific markers of autoimmune hepatitis (AIH). The exact mechanisms responsible for the development of these autoantibodies and leading to autoimmunity to this peculiar liver receptor remain elusive. Furthermore, loss of T cell tolerance to ASGPR has been demonstrated in patients with AIH, but it is poorly understood whether such liver-specific T cell responses bear a pathogenic potential and/or participate in the precipitation of AIH. Newly developed enzyme-linked immunosorbent assays have led to the investigation of the sensitivity and specificity of anti-ASGPR antibodies for AIH. The present review provides an overview of the diagnostic and clinical relevance of anti-ASGPR antibodies. A thorough investigation of the autoreactivity against ASGPR may assist efforts to understand liver autoimmunity in susceptible individuals.

p38 mitogen-activated protein kinase (p38 MAPK)-mediated autoimmunity: lessons to learn from ANCA vasculitis and pemphigus vulgaris

Evidence is beginning to accumulate that p38 mitogen activated protein kinase (p38 MAPK) signaling pathway plays an important role in the regulation of cellular and humoral autoimmune responses. The exact mechanisms and the degree by which the p38 MAPK pathway participates in the immune-mediated induction of diseases have started to emerge. This review discusses the recent advances in the molecular dissection of the p38 MAPK pathway and the findings generated by reports investigating its role in the pathogenesis of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and autoimmune hepatitis. Application of newly-developed protocols based on sensitive flow cytometric detection has proven to be a useful tool in the investigation of the phosphorylation of p38 MAPK within different peripheral blood mononuclear cell populations and may help us to better understand the enigmatic role of this signaling cascade in the induction of autoimmunity as well as its role in immunosuppressive-induced remission. Special attention is paid to reported data proposing a specific role for autoantibody-induced activation of p38 MAPK-mediated immunopathology in the pathogenesis of autoimmune blistering diseases and anti-neutrophilic antibody-mediated vasculitides.

Predicting and preventing autoimmunity: the case of anti-mitochondrial antibodies

To be able to predict who will develop autoimmune disease would allow for early treatment which may dramatically alter the course of the disease. In some cases, it may also lead to prevention of the disease development. The prediction of disease development is based on the analysis of risk factors which have been associated with the disease in question. These factors include genetic susceptibility, as well as immunological and environmental factors. One autoimmune disease that may serve as a model for disease prediction is primary biliary cirrhosis (PBC), an autoimmune liver disease affecting the small- and medium-sized bile ducts. PBC could be an ideal model due to recent advances in elucidating its genetic associations. As well, a variety of immunological and environmental risk factors have been well established. Indeed, the presence of PBC-specific antimitochondrial antibodies and/or antinuclear antibodies has been shown to be predictor of disease development and possibly prognosis. This review will examine the current evidence which suggests that we may potentially be able to predict the development of PBC in some individuals. These concepts may also be applied to autoimmune diseases in general.

Role for mycobacterial infection in pathogenesis of primary biliary cirrhosis?

Primary biliary cirrhosis (PBC) is a progressive cholestatic liver disease characterized by the immune-mediated destruction of biliary epithelial cells in small intrahepatic bile ducts. The disease is characterized by circulating antimitochondrial antibodies (AMAs) as well as disease-specific antinuclear antibodies, cholestatic liver function tests, and characteristic histological features, including granulomas. A variety of organisms are involved in granuloma formation, of which mycobacteria are the most commonly associated. This has led to the hypothesis that mycobacteria may be involved in the pathogenesis of PBC, along with other infectious agents. Additionally, AMAs are found in a subgroup of patients with mycobacterial infections, such as leprosy and pulmonary tuberculosis. Antibodies against species-specific mycobacterial proteins have been reported in patients with PBC, but it is not clear whether these antibodies are specific for the disease. In addition, data in support of the involvement of the role of molecular mimicry between mycobacterial and human mitochondrial antigens as triggers of cross-reactive immune responses leading to the loss of immunological tolerance, and the induction of pathological features have been published. Thus, antibodies against mycobacterial heat shock protein appear to cross-recognize AMA-specific autoantigens, but it is not clear whether these autoantibodies are mycobacterium-species-specific, and whether they are pathogenic or incidental. The view that mycobacteria are infectious triggers of PBC is intriguing, but the data provided so far are not conclusive.

Advances in the current treatment of autoimmune hepatitis

Current treatment strategies for autoimmune hepatitis are complicated by frequent relapse after drug withdrawal, medication intolerance, and refractory disease. The objective of this review is to describe advances that have improved treatment outcomes by defining the optimum objectives of initial therapy, managing relapse more effectively, identifying problematic patients early, and incorporating the new pharmacological interventions that have emerged as frontline and salvage therapies. Initial corticosteroid treatment should be continued until serum aminotransferase, γ-globulin, and immunoglobulin G levels are normal, and maintenance of this improvement for 3-8 months before liver tissue assessment. Improvement to normal liver tissue is the ideal histological result that justifies drug withdrawal, but it is achievable in only 22 % of patients. Minimum portal hepatitis, inactive cirrhosis, or minimally active cirrhosis is the most common treatment end point. Relapse after drug withdrawal warrants institution of a long-term maintenance regimen, preferably with azathioprine. Mathematical models can identify problematic adult patients early, as also can clinical phenotype (age ≤ 30 years and HLA DRB1 03), rapidity of treatment response (≤ 24 months), presence of antibodies to soluble liver antigen, and non-white ethnicity. The calcineurin inhibitors (cyclosporine and tacrolimus) can be effective in steroid-refractory disease; mycophenolate mofetil can be corticosteroid-sparing and effective for azathioprine intolerance; budesonide combined with azathioprine can be effective for treatment-naïve, non-cirrhotic patients. Standard treatment regimens for autoimmune hepatitis can be upgraded without adjustments that require major new expertise.

Epstein-barr virus as a trigger of autoimmune liver diseases

The pathogenesis of autoimmune diseases includes a combination of genetic factors and environmental exposures including infectious agents. Infectious triggers are commonly indicated as being involved in the induction of autoimmune disease, with Epstein-Barr virus (EBV) being implicated in several autoimmune disorders. EBV is appealing in the pathogenesis of autoimmune disease, due to its high prevalence worldwide, its persistency throughout life in the host's B lymphocytes, and its ability to alter the host's immune response and to inhibit apoptosis. However, the evidence in support of EBV in the pathogenesis varies among diseases. Autoimmune liver diseases (AiLDs), including autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC), have a potential causative link with EBV. The data surrounding EBV and AiLD are scarce. The lack of evidence surrounding EBV in AiLD may also be reflective of the rarity of these conditions. EBV infection has also been linked to other autoimmune conditions, which are often found to be concomitant with AiLD. This paper will critically examine the literature surrounding the link between EBV infection and AiLD development. The current evidence is far from being conclusive of the theory of a link between EBV and AiLD.

Asialoglycoprotein receptor (ASGPR) as target autoantigen in liver autoimmunity: lost and found

Asialoglycoprotein receptor (ASGPR) has attracted the attention of liver immunologists for many years. This liver-specific lectin was found to be a major B and T cell autoantigenic target in patients with autoimmune liver diseases, and in particular in autoimmune hepatitis (AIH). This review discusses the biological significance of ASGPR and its relevance to the pathogenesis of autoimmune and virus-triggered liver diseases. We also discuss emerging data on the diagnostic and clinical relevance of anti-ASGPR antibodies in light of recent reports based on commercially available anti-ASGPR enzyme-linked immunosorbent assays. Finally, we critically revisit the data reporting on disease-specific cellular immune responses against ASGPR and their relevance in relation to the pathogenesis of AIH.

A novel small molecule, (E)-5-(2,4-di-tert-butyl-6-((2,4-dioxothiazolidin-5-ylidene)methyl)phenyl)-5'-methyl-7,7'-dimethoxy-4,4'-bibenzo[d][1,3]dioxole-5,5'-dicarboxylate (7k), alleviates the development of D-galactosamine/lipopolysaccharide-induced acute liver failure by inhibiting macrophage infiltration and regulating cytokine expression

Acute liver failure (ALF) is a relatively rare liver disorder that leads to the massive death of hepatocytes. Our previous study reported that a novel small-molecule agent, (E)-5-(2,4-di-tert-butyl-6-((2,4-dioxothiazolidin-5-ylidene)methyl)phenyl)-5'-methyl-7,7'-dimethoxy-4,4'-bibenzo[d][1,3]dioxole-5,5'-dicarboxylate (7k), possessed potent anti-inflammatory activity. In the present study, we further evaluated the therapeutic effects of 7k on lipopolysaccharide (LPS)-induced ALF and investigated the mechanisms of action. Our results demonstrated that 7k inhibited the migration of RAW264.7 macrophages, blocked the activity of nuclear factor-κB protein, and dose-dependently down-regulated the production of interleukin (IL)-1β, tumor necrosis factor-α, and IL-6 as well as their corresponding mRNAs in RAW264.7 cells. Oral administration of 7k at a dose of 50 mg/kg significantly suppressed the serum level of enzyme activity and prevented the damage of liver tissue in D-galactosamine/LPS-induced ALF. Treatment with 7k also remarkably blocked the increase in the number of CD11b(+)- and CD68(+)-positive cells in the liver, and in vivo nuclear factor-κB activity, known to regulate inflammatory responses in many cell types, was effectively inhibited. The serum concentrations and hepatic mRNA expression of proinflammatory cytokines tumor necrosis factor-α, IL-1β, and IL-6 were markedly down-regulated in mice by the treatment of 7k. In summary, 7k alleviated the development and progression of D-galactosamine/LPS-induced ALF by inhibiting macrophage infiltration and regulating the expression of cytokines.

Urinary tract infection as a risk factor for autoimmune liver disease: from bench to bedside

Autoimmune liver diseases include autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis. A variety of environmental and genetic risk factors have been associated with these conditions. Recurrent urinary tract infections (rUTI) have been strongly associated with PBC, and to a lesser extent with AIH. These observations were initially based on the observation of significant bacteriuria in female patients with PBC. Larger epidemiological studies demonstrated that there was indeed a strong correlation between recurrent UTI and PBC. AIH has not been linked to recurrent UTI in epidemiological studies; however treatment of UTI with nitrofurantoin can induce AIH. As Escherichia coli is the most prevalent organism isolated in women with UTI, it has been suggested that molecular mimicry between microbial and human PDC-E2 (the main autoantigenic target in PBC) epitopes may explain the link between UTI and PBC. Multiple studies have demonstrated molecular mimicry and immunological cross-reactivity involving microbial and self-antigen mimics. This review will examine the literature surrounding UTI and autoimmune liver disease. This will include case reports and epidemiological studies, as well as experimental data.

Autoantibody-negative autoimmune hepatitis

Autoimmune hepatitis has a variable clinical phenotype, and the absence of conventional autoantibodies does not preclude its diagnosis or need for treatment. The goals of this review are to describe the frequency and nature of autoantibody-negative autoimmune hepatitis, indicate its outcome after corticosteroid treatment, and increase awareness of the diagnosis in patients with unexplained acute and chronic hepatitis. The frequency of presumed autoantibody-negative autoimmune hepatitis in patients with acute and acute severe presentations is ≤7%, and its frequency in patients with chronic presentations is 1-34%. Patients with acute presentations can have normal serum γ-globulin levels, centrilobular zone 3 necrosis, and low pre-treatment international diagnostic scores. Liver tissue examination is essential for the diagnosis, and hepatic steatosis can be a co-morbid feature. The comprehensive international scoring system can support but never override the clinical diagnosis pre-treatment, and non-standard serological markers should be sought if the clinical diagnosis is uncertain or the diagnostic score is low. A 3-month treatment trial with corticosteroids should be considered in all patients, regardless of the serological findings, and improvements have occurred in 67-87% of cases. Autoantibody-negative autoimmune hepatitis may be associated with an autoantibody outside the conventional battery; it may have a signature autoantibody that is still undiscovered, or its characteristic autoantibodies may have been suppressed or have a delayed expression. The pathogenic mechanisms are presumed to be identical to those of classical disease. Autoantibody-negative autoimmune hepatitis is an infrequent but treatable disease that must be considered in unexplained acute and chronic hepatitis.

Gender and the regulation of longevity: implications for autoimmunity

For humans and other animals, gender has an influence not only on their physical attributes, but also on life span. In humans, females have a longer life span than males. The reasons for this are not entirely clear. The role of gender in the regulation of longevity may be linked to gender specific genetic differences, including the expression of sex hormone patterns and the changes in these patterns during an individual's lifetime. In addition, the effect of sex hormones on other physiologic responses to environmental influences on cellular stress and oxidative damage may play a role in longevity. Gender can impact many disease states, including autoimmune diseases, and the factors that affect the development of autoimmune diseases and the regulation of longevity may share common mechanistic pathways. Other factors that may play a role include telomere and telomerase related differences, caloric restriction and changes in mitochondrial DNA. Inflammatory and regulatory pathways such as insulin/IGF signaling and Target of Rapamycin (TOR) signaling may also play a role in longevity and aging-related diseases such as Alzheimer's. The role of gender differences in the regulation of these pathways or factors is not entirely clear. The role of X-chromosome inactivation in longevity has also yet to be fully elucidated.

Immunopathogenesis of primary biliary cirrhosis: an old wives' tale

Primary biliary cirrhosis (PBC) is a cholestatic liver disease characterised by the autoimmune destruction of the small intrahepatic bile ducts. The disease has an unpredictable clinical course, but may progress to fibrosis and cirrhosis. Although medical treatment with urseodeoxycholic acid is largely successful, some patients may progress to liver failure requiring liver transplantation. PBC is characterised by the presence of disease specific anti-mitochondrial (AMA) antibodies, which are pathognomonic for PBC development. The disease demonstrates an overwhelming female preponderance and virtually all women with PBC present in middle age. The reasons for this are unknown; however several environmental and immunological factors may be involved. As the immune systems ages, it become less self tolerant, and mounts a weaker response to pathogens, possibly leading to cross reactivity or molecular mimicry. Some individuals display immunological changes which encourage the development of autoimmune disease. Risk factors implicated in PBC include recurrent urinary tract infection in females, as well as an increased prevalence of reproductive complications. These risk factors may work in concert with and possibly even accelerate, immune system ageing, contributing to PBC development. This review will examine the changes that occur in the immune system with ageing, paying particular attention to those changes which contribute to the development of autoimmune disease with increasing age. The review also discusses risk factors which may account for the increased female predominance of PBC, such as recurrent UTI and oestrogens.

Pathogenesis of autoimmune hepatitis

The mechanisms underlying the pathogenesis of autoimmune hepatitis are not fully understood, though there is growing evidence that genetic predisposition, molecular mimicry and/or impairment of regulatory T-cells are involved in the initiation and perpetuation of the autoimmune liver attack. The histological picture of interface hepatitis, characterized by a dense portal mononuclear cell infiltrate, was the first to suggest an autoaggressive cellular immune attack in the pathogenesis of this condition. Liver damage is likely to be orchestrated by CD4(pos) T-cells recognizing an autoantigenic liver peptide. For autoimmunity to arise, the peptide must be presented by antigen-presenting cells to naïve CD4(pos) T-helper (Th0) cells. Once activated, Th0-cells can differentiate into Th1-, Th2-, or Th17-cells, initiating a cascade of immune reactions that are determined by the cytokines they produce. Autoantigen recognition and the above effector mechanisms are opposed by regulatory T-cells, a cell subset numerically and functionally impaired in autoimmune hepatitis.

Towards systemic sclerosis and away from primary biliary cirrhosis: the case of PTPN22

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by immune-mediated destruction of the small and medium size intrahepatic bile ducts. PBC patients often have concomitant autoimmune diseases, which are most often autoimmune thyroid disease, as well as Sicca syndrome. Occasionally, some PBC patients will also have systemic sclerosis of the limited cutaneous type (lcSSc). Conversely, up to one-fourth of SSc patients are positive for antimitochondrial antibody, the serologic hallmark of PBC. It is also common for SSc patients to have concomitant autoimmune disease, which may include PBC in rare cases. This has led to speculation of shared environmental and/or genetic factors, which lead to the development of PBC in SSc patients and vice versa. Recent genetic studies have revealed associations with several genes in both SSc and PBC. PTPN22 is one gene that has been associated with SSc, but not with PBC. It may be argued that some SSc patients with a particular genotype, which shares genes found in both conditions may develop PBC. Likewise, particular genes such as PTPN22 may infer susceptibility to SSc alone. The presence of PTPN22 may also contribute to the development of SSc in PBC patients. The lack of a large number of overlapping genes may, in part, explain the relative rarity of PBC with SSc and vice versa. This review will examine the literature surrounding the genetic associations of PBC and SSc, and the role of PTPN22 in particular.

Role of NKT cells in autoimmune liver disease

The three main broad categories of autoimmune liver disease are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). The etiologies of these diseases are still incompletely understood, but seem to involve a combination of immune, genetic and environmental factors. Although each of these diseases has relatively distinct clinical, serologic and histological profiles, all of them share common pathways of immune-mediated liver injury. The development of autoimmune liver diseases is thought to be due to an imbalance of proinflammatory and anti-inflammatory immune responses within the liver, with proinflammatory immune responses being upregulated and anti-inflammatory ones downregulated. The available evidence, suggest that during autoimmune responses within the liver, "self" antigens are presented by antigen presenting cells (APCs) which then activate, directly and/or indirectly, NKT cells and other innate immune cells within the liver. Importantly, the hepatic innate immune system plays an increasingly recognized role in the development and propagation of autoimmune liver injury. NKT cells predominantly reside in the liver sinusoids, and through their ability to rapidly produce a wide variety of cytokines (e.g. Th1, TH2, Th17 cytokine patterns), are a critical checkpoint that bridges innate and adaptive immune responses. Specifically, activated NKT cells are capable of transactivating other innate and adaptive immune cells within the liver to amplify and regulate subsequent immune responses within the liver. It has been hypothesized that NKT cells in the setting of autoimmune liver disease can play diverse roles, including driving both anti-inflammatory and proinflammatory responses, as well as regulating the hepatic recruitment of other types of immunoregulatory cells, including regulatory T cells.

Cytokine profiles affecting the pathogenesis of autoimmune hepatitis in Japanese patients

AIM

  Autoimmune hepatitis (AIH) is a chronic hepatitis of unknown etiology, although several cytokines have been implicated in its pathogenesis and severity. This study investigated the relationship between circulating cytokines in the pretreatment phase and remission following corticosteroid therapy phase in Japanese AIH patients.

METHODS

  A total of 28 cytokines were measured simultaneously by multiple bead array technology in the sera of 40 patients with AIH collected during pretreatment and remission phases.

RESULTS

  Interleukin (IL)-12p40, interferon-γ-inducible protein (IP-10), macrophage inflammatory protein (MIP)-1α, MIP-1β, IL-17F and IL-18 were significantly decreased during remission from pretreatment stage levels. The level of IP-10 in the pretreatment phase was correlated with serum levels of alanine aminotransferase.

CONCLUSION

  Our results suggest that a complex interplay of several cytokines, especially pro-inflammatory and T-helper 17 cytokines and regulatory T-cell suppression by IL-12p40 may play a pivotal role in the pathogenesis of AIH.

Dectin-1 targeting delivery of TNF-α antisense ODNs complexed with β-1,3-glucan protects mice from LPS-induced hepatitis

Antisense therapy, the first concept of oligonucleotide therapeutics, was proposed more than two decades ago. However, the lack of suitable delivering carriers continues to be a major obstacle to practical therapy. In this study, we present a novel complex consisting of β-1,3-glucan and antisense oligonucleotide (AS-ODN) as a new candidate of the carriers. We used schizophyllan (SPG) as a β-1,3-glucan and an AS-ODN sequence to suppress tumor necrosis factor alpha (TNF-α), where the AS-ODN has a (dA)(60) tail to induce complex with SPG. When the complexes were applied to peritoneal macrophages, they were incorporated into the cells via dectin-1 (a β-1,3-glucan receptor expressed on antigen presenting cells) and suppressed lipopolysaccharide (LPS)-induced TNF-α secretion. In-vivo, AS-ODN/SPG decreased the secretion of TNF-α in serum and drastically reduced the inflammation of LPS-induced hepatitis. This new complex could overcome the long outstanding problem for antisense therapy because of its complexation ability, non-toxicity and high target specificity.