Autoimmune hepatitis: the role of environmental risk factors: a population-based study

Alcohol Consumption and Autoimmune Diseases

Alcohol is the second-most misused substance after tobacco. It has been identified as a causal factor in more than 200 diseases and 5.3% of all deaths and is associated with significant behavioral, social, and economic difficulties. As alcohol consumption may modulate the immune system's regulatory mechanisms to avoid attacking the body's tissues, it has been proven to play a dichotomic role in autoimmune diseases (ADs) based on the quantity of consumption. In this review, we report updated evidence on the role of alcohol in ADs, with a focus on alcohol addiction and the human biological immune system and the relationship between them, with alcohol as a risk or protective factor. Then, in this narrative review, we report the main evidence on the most studied ADs where alcohol represents a key modulator, including autoimmune thyroiditis, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, diabetes, allergic rhinitis, and primary biliary cholangitis. Alcohol at low-moderate dosages seems mostly to have a protective role in these diseases, while at higher dosages, the collateral risks surpass possible benefits. The specific mechanisms by which low-to-moderate alcohol intake relieves AD symptoms are not yet fully understood; however, emerging studies suggest that alcohol may have a systemic immunomodulatory effect, potentially altering the balance of anti-inflammatory innate and adaptive immune cells, as well as cytokines (via the NF-κB or NLRP3 pathways). It might influence the composition of the gut microbiome (increasing amounts of beneficial gut microbes) and the production of their fatty acid metabolites, such as short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs), as well as elevated concentrations of acetate, high-density lipoprotein (HDL), and nitric oxide (NO). Unfortunately, a definite acceptable daily intake (ADI) of ethanol is complicated to establish because of the many mechanisms associated with alcohol consumption such that despite the interesting content of these findings, there is a limit to their applicability and risks should be weighed in cases of alcoholic drinking recommendations. The aim of future studies should be to modulate those beneficial pathways involved in the alcohol-protective role of ADs with various strategies to avoid the risks associated with alcohol intake.

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.

Microbiome and Genetic Factors in the Pathogenesis of Liver Diseases

Our genetic background has not changed over the past century, but chronic diseases are on the rise globally. In addition to the genetic component, among the critical factors for many diseases are inhabitants of our intestines (gut microbiota) as a crucial environmental factor. Dysbiosis has been described in liver diseases with different etiologies like non-alcoholic fatty liver disease (NAFLD), alcohol-related liver disease (ALD), viral hepatitis, autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC), cirrhosis, hepatocellular carcinoma (HCC). On the other hand, new technologies have increased our understanding of liver disease genetics and treatment options. Genome-wide association studies (GWAS) identify unknown genetic risk factors, positional cloning of unknown genes associated with different diseases, gene tests for single nucleotide variations (SNVs), and next-generation sequencing (NGS) of selected genes or the complete genome. NGS also allowed studying the microbiome and its role in various liver diseases has begun. These genes have proven their effect on microbiome composition in host genome–microbiome association studies. We focus on altering the intestinal microbiota, and supplementing some bacterial metabolites could be considered a potential therapeutic strategy. The literature data promote probiotics/synbiotics role in reducing proinflammatory cytokines such as TNF-α and the interleukins (IL-1, IL-6, IL-8), therefore improving transaminase levels, hepatic steatosis, and NAFLD activity score. However, even though microbial therapy appears to be risk-free, evaluating side effects related to probiotics or synbiotics is imperative. In addition, safety profiles for long-term usage should be researched. Thus, this review focuses on the human microbiome and liver diseases, recent GWASs on liver disease, the gut-liver axis, and the associations with the microbiome and microbiome during/after liver disease therapy.

Global incidence and prevalence of autoimmune hepatitis, 1970-2022: a systematic review and meta-analysis

Background

Autoimmune hepatitis (AIH) varies significantly in incidence and prevalence across countries and regions. We aimed to examine global, regional, and national trends in incidence and prevalence of AIH from 1970 to 2022.

Methods

We conducted a thorough search of the PubMed/MEDLINE, Embase, CINAHL, Google Scholar, and Cochrane databases from database inception to August 9, 2023, using the search term "autoimmune hepatitis" in combination with "incidence," "prevalence," or "trend." Only general population-based observational studies with larger samples sizes were considered for inclusion. Studies that recruited convenience samples, and those with fewer than 50 participants were excluded. Summary data were extracted from published reports. A random effects model was used and pooled estimates with 95% CI were used to calculate the incidence and prevalence of AIH. Heterogeneity was evaluated using the I2 statistic. The study protocol was registered with PROSPERO, CRD42023430138.

Findings

A total of 37 eligible studies, encompassing more than 239 million participants and 55,839 patients with AIH from 18 countries across five continents, were included in the analysis. Global pooled incidence and prevalence of AIH were found to be 1.28 cases per 100,000 inhabitant-years (95% CI, 1.01-1.63, I2 = 99·51%; number of studies, 33; sample population, 220,673,674) and 15.65 cases per 100,000 inhabitants (95% CI, 13.42-18.24, I2 = 99·75%; number of studies, 26; sample population, 217,178,684), respectively. The incidence of AIH was greater in countries with high Human Development Index (>0.92), in North America and Oceania (compared with Asia), among females, adults (compared with children), and high latitude (>45°). Similar patterns in AIH prevalence were observed. Pooled AIH prevalence increased gradually from 1970 to 2019 (1970-1999; 9.95 [4.77-15.13], I2 = 95·58% versus 2015-2022; 27.91 [24.86-30.96], I2 = 99·32%; cases per 100,000 inhabitants). The overall incidence and prevalence of AIH, as well as some subgroup analyses of the studies, displayed asymmetry in the funnel plots, suggesting potential evidence of publication bias.

Interpretation

AIH incidence and prevalence have increased significantly and exhibit substantial variation across regions worldwide. Further research is required to assess the incidence and prevalence of AIH, specifically in South America and Africa.

Funding

National Research Foundation of Korea.

The progress of autoimmune hepatitis research and future challenges

Autoimmune hepatitis (AIH) is a chronic liver inflammatory disease with various immune system manifestations, showing a global trend of increased prevalence. AIH is diagnosed through histological abnormalities, clinical manifestations, and biochemical indicators. The biochemical markers involve interfacial hepatitis, transaminase abnormalities, positive autoantibodies, etc. Although AIH pathogenesis is unclear, gene mutations and immunological factors could be the leading factors. AIH usually presents as a chronic liver disease and sometimes as acute hepatitis, making it challenging to distinguish it from drug-related hepatitis due to similar clinical symptoms. Normalizing transaminases and serum IgG levels is essential in assessing the remission status of AIH treatment. Glucocorticoids and azathioprine are the first-line AIH treatment, with lifelong maintenance therapy in some patients. The quality of life and survival can be improved after appropriate treatment. However, certain limitations jeopardize the quality of treatment, including long treatment cycles, side effects, poor patient compliance, and inability to inhibit liver fibrosis and cirrhosis. Accurate AIH animal models will help us understand the pathophysiology of the disease while providing fresh perspectives for avoiding and treating AIH. This review will help us understand AIH better, from the cellular and molecular causes to the clinical features, and will provide insight into new therapy techniques with fewer side effects.

Autoimmune hepatitis presenting with concomitant chronic pancreatitis

Autoimmune Hepatitis (AIH) is a progressive form of chronic hepatitis, with periods of remissions and exacerbations. Diagnosis includes abnormally high levels of immunoglobulins and multiple autoantibodies. Clinical presentation is variable, with a spectrum extending from asymptomatic cases to fulminant liver failure. Symptoms include abdominal pain, malaise, fatigue, and small joint arthralgia. We present a case of a 36-year-old male with a past medical history of alcohol dependence and acute pancreatitis who was diagnosed with AIH. There is limited data regarding patients with concomitant AIH and pancreatitis. Our patient presented with AIH with secondary acute on chronic pancreatitis, in the absence of additional autoimmune manifestations. The mechanism of AIH remains poorly understood; however, there is an association between the HLA gene and AIH. Genetic studies have shown HLA-DRB1*0301 and HLA-DRB1*0401 as primary and secondary genotypes susceptible to AIH, as well as genetic variants with CARD10 and SH2B3. Products secondary to metabolism of ETOH such as alcohol dehydrogenase, malondialdehyde, and acetaldehyde, can lead to development of autoantibodies. Additional research is indicated to evaluate the relationship between AIH and acute pancreatitis.

Incorporating the Molecular Mimicry of Environmental Antigens into the Causality of Autoimmune Hepatitis

Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.

Binge drinking does not appear to have an adverse effect on non-alcoholic fatty liver disease: Findings from a study of four First Nations communities

BACKGROUND: Binge drinking and non-alcoholic fatty liver disease (NAFLD) are common health problems throughout the world. However, the impact of binge drinking on NAFLD has yet to be described. The objective of this study was to document the extent of liver disease in community-based NAFLD patients who self-reported monthly binge drinking and compare the findings to NAFLD patients from the same communities who denied binge drinking (controls). METHODS: The study was undertaken in four Manitoba First Nations communities where the sale and consumption of alcoholic beverages are prohibited but visits to urban centres are common. Binge drinkers were retrospectively matched 1:2 by age, sex, and body mass index (BMI) with controls. NAFLD was diagnosed by ultrasonographic features of excess fat in the liver in individuals with no alternative, non-metabolic explanation for fatty infiltration of the liver. Hepatic inflammation and function were determined by standard liver biochemistry testing and fibrosis by FIB-4 levels and hepatic elastography. RESULTS: Of 546 NAFLD patients, 88 (16%) attested to binge drinking. The mean age of binge drinkers was 40 (SD 13) years; 51% were male; and the mean BMI was 34 (SD 7). Compared with controls, binge drinkers had similar liver biochemistry results (alanine and aspartate aminotransferases: 41 [SD 39] and 36 [SD 30] versus 36 [SD 36] and 31 [SD 27] U/L, p = 0.35 and p = 0.37, respectively), FIB-4 values (0.75 [SD 0.55] versus 0.72 [SD 0.44], p = 0.41, respectively), and hepatic elastrography (6.6 [SD 3.9] versus 6.2 [SD 2.9] kPa, p = 0.37, respectively) findings. CONCLUSIONS: In this study population, monthly binge drinking did not appear to impact the severity of NAFLD.

Low vitamin D concentrations and BMI are causal factors for primary biliary cholangitis: A mendelian randomization study

Backgrounds

Observational studies have identified associations between smoking, alcohol use, body mass index (BMI), and the levels of vitamin D with primary biliary cholangitis (PBC). However, there was a lack of randomization control studies to estimate the causal relationship. This study was to investigate the causal estimates for the effects of those risk factors on PBC.

Methods

The genetic instrument variants were extracted from genome-wide association studies in European ancestry. Two-sample mendelian randomization (MR) and multivariable mendelian randomization were used to determine genetically causal estimates. Primary analyses consisted of random-effects and fix-mode inverse-variance-weighted methods, followed by secondary sensitivity analyses to verify the results.

Results

Our study showed that BMI was a causal factor for PBC (OR 1.35; 95% CI=1.03-1.77; p=0.029). In addition, we found that serum vitamin D levels had a protective effect on PBC after adjusting for BMI (OR 0.51; 95% CI=0.32-0.84; p=0.007). However, we failed to identify evidence supporting that genetic causal effect of smoking and alcohol intake were associated with PBC in European countries.

Conclusion

Our results enriched findings from previous epidemiology studies and provided evidence from MR that serum vitamin D concentrations and BMI were independent causal factors for PBC, suggesting that ensuing vitamin D sufficiency and healthy lifestyles might be a cost-effective measure for early intervention for PBC.

CCN1 Promotes Inflammation by Inducing IL-6 Production via α6β1/PI3K/Akt/NF-κB Pathway in Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease with unknown etiology. CCN1, an extracellular matrix-associated protein, is associated with carcinoma, inflammation, liver fibrosis, and even autoimmune diseases. However, the role that CCN1 plays in AIH has remained undetermined. In this study, expression of CCN1 in liver was detected by real-time PCR, western blot and immunohistochemistry (IHC). CCN1 level in serum was detected by ELISA. Diagnostic value of CCN1 was determined by receiver operating characteristic (ROC) curve analysis. CCN1 conditional knockout (CCN1^fl/flCre⁺) mice were generated by mating CCN1^fl/fl C57BL/6J and CAG-Cre-ERT C57BL/6J mice. Autoimmune hepatitis mice model was induced by concanavalin A (ConA). IKKα/β, IκBα, NF-κB p65 and Akt phosphorylation were determined by western blot. NF-κB p65 nuclear translocation was examined by immunofluorescence. Here, we found that CCN1 was over-expressed in hepatocytes of AIH patients. CCN1 level also increased in serum of AIH patients compared to healthy controls (HC). ROC curve analysis results showed that serum CCN1 was able to distinguish AIH patients from HD. In ConA induced hepatitis mice model, CCN1 conditional knockout (CCN1^fl/flCre⁺) attenuated inflammation by reducing ALT/AST level and IL-6 expression. In vitro, CCN1 treatment dramatically induced IL-6 production in LO2 cells. Moreover, the production of IL-6 was attenuated by CCN1 knockdown. Furthermore, we showed that CCN1 could activate IL-6 production via the PI3K/Akt/NF-κB signaling pathway by binding to α6β1 receptor. In summary, our results reveal a novel role of CCN1 in promoting inflammation by upregulation of IL-6 production in AIH. Our study also suggests that targeting of CCN1 may represent a novel strategy in AIH treatment.

The intestinal and biliary microbiome in autoimmune liver disease-current evidence and concepts

Autoimmune liver diseases are a group of immune-mediated liver diseases with three distinct entities, including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. The interplay of genetic and environmental factors leads to the breakdown of self-tolerance, resulting in hyper-responsiveness, and auto-aggressive immune activation. Emerging evidence links autoimmune liver diseases with alterations of the commensal microbiome configuration and aberrant immune system activation by microbial signals, mainly via the gut-liver axis. Thus, the microbiome is a new frontier to deepen the pathogenetic understanding, uncover biomarkers, and inspire innovative treatments. Herein, we review the current evidence on the role of the microbiome in autoimmune liver diseases from both clinical and basic research. We highlight recent achievements and also bottlenecks and limitations. Moreover, we give an outlook on future developments and potential for clinical applications.

Patients with Autoimmune Hepatitis Report Lower Lifetime Coffee Consumption

BACKGROUND

Coffee drinking has been associated with decreased risk of some autoimmune diseases as well liver disease and outcomes. Environmental factors, such as coffee consumption, are yet to be assessed among patients with autoimmune hepatitis (AIH).

AIM

We sought to investigate the relationship between coffee consumption and risk of AIH utilizing the Genetic Repository of Autoimmune Liver Disease and Contributing Exposures (GRACE) database.

METHODS

Lifetime coffee drinking was collected from 358 AIH patients (cases) and 564 volunteers (controls) from primary care visits. Groups were compared utilizing the Wilcoxon rank sum test for continuous variables and the Chi-square test for discrete variables. Logistic regression was used to analyze the effects of different coffee parameters (time, frequency, and cups) after adjusting for age, sex, education, smoking status, BMI, and daily activity.

RESULTS

24.6% of AIH patients never drank coffee compared to 15.7% of controls (p < 0.001), and only 65.6% were current drinkers compared with 77% of controls (p < 0.001). Among "ever" coffee drinkers, AIH patients consumed fewer lifetime cups of coffee per month (45 vs. 47 for controls, p < 0.001) and spent less percentage of life drinking coffee (62.5% vs. 69.1% for controls, p < 0.001). Concurrent inflammatory bowel disease was higher among AIH patients than controls (5.7% vs. 1.2%, p < 0.001), yet did not significantly contribute to "never" coffee drinking status. The relationship between lower coffee consumption and AIH persisted even after controlling for covariates.

CONCLUSIONS

Coffee consumption is lower among patients with AIH compared to controls.

We Are Not Immune: Racial and Ethnic Disparities in Autoimmune Liver Diseases

Autoimmune liver diseases are attributed to a complex interplay of biologic, acquired, and environmental factors. Increased prevalence, later stage at presentation, worse response to standard therapy, and transplant-related disparities have all been reported in racial and ethnic minorities such as Black and Latinx patients with autoimmune liver diseases. While biology and inherited genetic predispositions may partly explain these disparities, definitive and universal genetic variations underlying these differences in outcomes have not been defined. Nonetheless, socioeconomic status, access to health care, environmental and societal factors, and implicit provider bias can all contribute to poor patient outcomes. There remains an unmet need to understand and mitigate the factors contributing to health inequity in autoimmune liver diseases. In this review, we summarize the data on racial and ethnic disparities in presentation, treatment response, and outcomes pertaining to autoimmune liver diseases in minority populations, on the premise that understanding disparities is the first step toward reaching health equity.

Environmental risk factors are associated with autoimmune hepatitis

BACKGROUND

Failure of immunologic homeostasis and resultant hepatocyte destruction in autoimmune hepatitis (AIH) is likely the result of environmental triggers within a permissive genetic architecture.

AIMS

We aimed to identify risk factors associated with AIH in a well-phenotyped AIH cohort.

METHODS

We prospectively collected environmental questionnaires from 358 AIH cases and 563 healthy controls. Response frequencies were compared using logistic regression, adjusting for age at recruitment, sex and education.

RESULTS

AIH cases were more likely to ever have a urinary tract infection (UTI) (53.6% vs 33.9%, P < .001) and recurrent UTI (more than 1 per year) (23.5% vs 15.9%, P = .002) compared to controls. Female cases more frequently had ever used oral contraceptives (83.0% vs 73.7%, P = .006), fewer pregnancies (median = 1 vs 3, P < .001) and less often used hormone replacement therapy compared to controls (28.5% vs 60.1%, P < .001). Current smoking was more prevalent in cases (18.9% vs 7.4%, P = .022), yet no difference according to historical smoking behaviours was observed. Finally, cases were less likely to have history of mumps (32.4% vs 53.1%, P = .011) and rheumatic fever (1.1% vs 4.4%, P = .028), but reported higher vaccination frequency to chicken pox (38% vs 28.1%), measles (66.5% vs 39.3%), mumps (58.7% vs 34.6%), rubella (55.3% vs 32.7%), pertussis (59.8% vs 40.1%) and pneumococcus (47.2% VS 39.4%) (P < .002).

CONCLUSIONS

Environmental factors are important in AIH pathogenesis. Replication of these findings and prospective examination may provide new insight into AIH onset and outcomes.

Impact of genetic and environmental factors on autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic non-resolving liver disease characterized by diffuse hypergammaglobulinemia, the presence of autoantibodies and characteristic histological findings. The disease can have catastrophic outcome with the development of end-stage liver disease if misdiagnosed/undiagnosed and left untreated. AIH pathogenesis remains obscure and the main hypothesis supports its development in genetically predisposed individuals after being exposed to certain environmental triggers. Genetic predisposition is linked to the presence of certain HLA alleles, mainly HLA-DR3 and HLA-DR4. However, a wide number of non-HLA epitopes have also been associated with the disease although data vary significantly among different ethnic groups. Therefore, it is likely that epigenetic alterations may also play a crucial role in disease's pathogenesis, although not yet extensively studied. The aim of this review was to summarize the genetic and environmental factors that have been associated with AIH, but also to open new insights towards the role of epigenetic modifications in the etiology of the disease.

The effects of binge drinking on healthy and diseased livers

The estimated global prevalence of alcohol abuse is 5%–15%, with 15%–20% of these individuals being considered binge drinkers. Despite the high prevalence, the effects of binge drinking on healthy and diseased livers remain unclear. This review focuses on the effects of binge drinking in adults with otherwise healthy livers and those with a variety of common underlying chronic liver diseases.

Familial associations between autoimmune hepatitis and primary biliary cholangitis and other autoimmune diseases

Autoimmune hepatitis (AH) and primary biliary cirrhosis (PBC) are autoimmune diseases (AIDs) targeting cellular components of the liver. Being rare diseases, limited data are available about familial risks among these AIDs (concordant) or between them and other AIDs (discordant). We aimed to carry out an unbiased study on these AIDs based on medically diagnosed patients. We collected data on patients diagnosed in Swedish hospitals with AH, PBC and other AIDs and calculated familial standardized incidence ratios (SIRs) for concordant and discordant familial relative risks. The number of AH patients was 6,269, of whom 43.0% were male; patient numbers for PBC were 4,269, with 17.8% males. AH accounted for 0.8% and 0.6% of all hospitalized AIDs in Sweden. For AH only the familial risk between siblings was significant (3.83). For PBC the risks for offspring of parents (9.05) and siblings (10.88) were high, but only risk for females was significant. Spousal risks were very high, 5.91 and 6.07 for AH. Risk for AH was 2.21 in families of PBC, and it was 2.47 for PBC in families of AH patients. Among other AIDs, 14 showed a significant association with AH, compared to 16 AIDs with PBC. The surprising finding in this nation-wide family study on medically diagnosed patients was the high risk for AH (6.0) between spouses, which exceed the risk between siblings, suggesting the existence of strong environmental risk factors. AH and PBC were associated with multiple other AIDs. The results call attention to environmental factors in AID etiology which should also be in focus in taking anamnestic data from patients.

Regulatory T Cells in Autoimmune Hepatitis: Unveiling Their Roles in Mouse Models and Patients

Autoimmune hepatitis (AIH) is a severe and chronic liver disease, and its incidence has increased worldwide in recent years. Research into the pathogenesis of AIH remains limited largely owing to the lack of suitable mouse models. The concanavalin A (ConA) mouse model is a typical and well-established model used to investigate T cell-dependent liver injury. However, ConA-induced hepatitis is acute and usually disappears after 48 h; thus, it does not mimic the pathogenesis of AIH in the human body. Several studies have explored various AIH mouse models, but as yet there is no widely accepted and valid mouse model for AIH. Immunosuppression is the standard clinical therapy for AIH, but patient side effects and recurrence limit its use. Regulatory T cells (Tregs) play critical roles in the maintenance of immune homeostasis and in the prevention of autoimmune diseases, which may provide a potential therapeutic target for AIH therapy. However, the role of Tregs in AIH has not yet been clarified, partly because of difficulties in diagnosing AIH and in collecting patient samples. In this review, we discuss the studies related to Treg in various AIH mouse models and patients with AIH and provide some novel insights for this research area.

Incidence, prevalence and mortality of autoimmune hepatitis in England 1997-2015. A population-based cohort study

BACKGROUND & AIMS

There are few population-based studies of the incidence and mortality of autoimmune hepatitis. The burden of the disease and how it has changed over time have not been fully explored. We conducted a population-based cohort study on the incidence and mortality of autoimmune hepatitis in England, 1997-2015.

METHODS

From the Clinical Practice Research Datalink we included 882 patients diagnosed with autoimmune hepatitis in England, 1997-2015. The patients were followed through 2015, and we calculated the sex- and age-standardized incidence and prevalence of autoimmune hepatitis. We examined variation in incidence by sex, age, calendar year, geographical region and socioeconomic status, and incidence rate ratios were calculated with Poisson regression. We calculated all-cause and cause-specific mortality.

RESULTS

The overall standardized incidence rate of autoimmune hepatitis was 2.08 (95% confidence interval 1.94-2.22) per 100,000 population per year, higher in women, higher in older age and independent of region and socioeconomic status. From 1997 to 2015 the incidence doubled from 1.27 (95% confidence interval 0.51-2.02) to 2.56 (95% confidence interval 1.79-3.33) per 100,000 population per year. The 10-year cumulative all-cause mortality was 31.9% (95% confidence interval 27.6-36.5), and the 10-year cumulative liver-related mortality, including hepatocellular carcinoma was ~10.5%.

CONCLUSIONS

This population-based study showed that the incidence of autoimmune hepatitis doubled over an eighteen-year period. The incidence was particularly high in older women and was similar across all regions of England and independent of socioeconomic status. Patients with autoimmune hepatitis had a high mortality.

Diffuse Systemic Sclerosis in a Patient with Primary Biliary Cirrhosis and Autoimmune Hepatitis Overlap Syndrome: A Case Report

Systemic sclerosis (SSc) is a chronic systemic disease of unknown etiology characterized by vasculopathy, excessive accumulation of extracellular matrix, and fibrosis of the skin and other internal organs. Although its etiology remains elusive, approximately one third of SSc patients presents with additional autoimmune disease, which suggests that an autoimmune mechanism is a major component of the underlying pathophysiology. On the other hand, primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) are two main autoimmune liver diseases. A 41-year-old female previously diagnosed with PBC/AIH overlap syndrome presented with multiple, painful brownish to erythematous firm patches on the hands, arms, axillae, neck, abdomen, and thighs. Laboratory work-up yielded positive results for anti-nuclear antibody, anti-Ro/Sjögren's-syndrome-related antigen A autoantibodies, and perinuclear anti-neutrophil cytoplasmic antibodies while punch biopsy of her left hand showed characteristics that are consistent with scleroderma. Herein, we report the first case of a patient with diffuse cutaneous SSc and concurrent PBC/AIH overlap syndrome and suggest that this coexistence of multiple autoimmune diseases is not a coincidence but rather that a common autoimmune pathogenesis may exist.

Extrahepatic Autoimmune Diseases are Prevalent in Autoimmune Hepatitis Patients and Their First-Degree Relatives: Survey Study

Background

Concurrent autoimmune illnesses contribute to increased medical burden and reduced quality of life in patients with autoimmune hepatitis (AIH). The frequency of coexisting autoimmune conditions among North American patients with AIH and their families remains incomplete. Challenges associated with disease capture in the electronic medical record, high study costs, and geographic spread of patients are formidable barriers to understanding the extent of concurrent autoimmune conditions in these groups.

Objective

This objective of this study was to examine the frequency of extrahepatic autoimmune diseases (EHAD) among AIH cases and healthy controls as well as their first-degree relatives using social networking sites (SNS).

Methods

We developed a 53-question survey detailing the history of autoimmune diseases. A survey link was posted at routine intervals within specific Web-based cohorts on SNS. Healthy controls, without self-reported autoimmune liver disease, were recruited from Amazon’s Mechanical Turk. Continuous variables were summarized using medians and P values obtained with the Wilcoxon rank-sum test. Categorical variables were compared using the chi-square test.

Results

Compared with controls (n=1162), cases (n=306) were more likely to be older (median age: 49 vs 33 years), female (284/306, 92.81% vs 955/1162, 82.18%), and have an EHAD (128/306, 41.83% vs 218/1162, 18.76%; P=.001). The most frequent EHADs among cases were thyroid disease (49/306, 16.01% ), Sjögren syndrome (27/306, 8.82%), Raynaud phenomenon (23/306, 7.52%), and psoriasis (22/306, 7.19%). Overall, 55.88% (171/306) of cases and 35.71% (1601/4484) of controls reported at least 1 first-degree relative (FDR) with a history of EHAD (P=.001). Cases had a significantly higher risk of EHAD than controls after the adjustment for age, sex, race, and body mass index: odds ratio 2.46 (95% CI 1.8-3.3); P=.001.

Conclusions

Patients with AIH report higher prevalence of coexistent EHAD than healthy controls, and their FDRs are also more likely to have autoimmune disorders.

Family occurrence of autoimmune hepatitis: A Danish nationwide registry-based cohort study

BACKGROUND & AIMS

It is widely believed that autoimmune hepatitis accumulates in families, but the degree of familial clustering has not been clarified. We conducted a population-based study on the family occurrence of autoimmune hepatitis.

METHODS

Through Danish nationwide registries we identified 8,582 first-degree and 9,230 second-degree relatives of index patients diagnosed with autoimmune hepatitis in 1994-2015; and 64 co-twins of index patients diagnosed with autoimmune hepatitis in 1977-2011. For first- and second-degree relatives we calculated the sex- and age-adjusted standardized incidence ratio of autoimmune hepatitis relative to the general population, and we calculated the cumulative risk, i.e. the cumulative incidence, of developing autoimmune hepatitis from the time of the index patient's diagnosis. For co-twins, we estimated the standardized incidence ratio and the concordance rate of autoimmune hepatitis.

RESULTS

In first-degree relatives, there were six incident autoimmune hepatitis diagnoses during 64,020 years of follow-up: the standardized incidence ratio was 4.9 (95% CI 1.8-10.7), and the 10-year cumulative risk was 0.10% (95% CI 0.04-0.23). In the second-degree relatives, there were no incident autoimmune hepatitis diagnoses (expected number assuming incidence rate as in the Danish general population = 0.8). In the co-twins, there was one incident autoimmune hepatitis diagnosis during 1,112 years of follow-up, and the standardized incidence ratio was 53.9 (95% CI 1.4-300.4). The probandwise concordance rate, a measure of heritability, was higher in monozygotic than in dizygotic twins (8.7% [95% CI 1.1-28.0] vs. 0%).

CONCLUSIONS

This nationwide study indicates that only first-degree relatives of index patients with autoimmune hepatitis are at increased risk of autoimmune hepatitis from the time of the index patient's diagnosis, but the absolute risk is very low.

LAY SUMMARY

Autoimmune hepatitis is a chronic liver disease caused by a dysfunctional immune system. It is widely believed that autoimmune hepatitis accumulates in families. We studied the family members of patients with autoimmune hepatitis from the entire Danish population. We found that autoimmune hepatitis does accumulate in families, but the risk of autoimmune hepatitis in the family members is very low.

Severe hepatitis arising from ipilimumab administration, following melanoma treatment with nivolumab

After 4 weeks of the last dose of nivolumab, a 59-year-old man with stage IV melanoma was subject to treatment with ipilimumab. After 5 weeks, the patient developed severe hepatitis, showing markedly elevated levels of both aspartate aminotransferase and alanine aminotransferase (>2000 U/l). Using pulse steroid therapy with 1000 mg/d of methylprednisolone, liver function initially improved, but then deteriorated upon dosage reduction. Subsequently, mycophenolate mofetil (MMF) was administered at a dose of 2 g/d in addition to the corticosteroid, which resulted in aspartate aminotransferase and alanine aminotransferase levels gradually improving to grade 1, and the corticosteroid dose was successfully reduced to 0.5 mg/kg/d of oral prednisolone. Liver function then remained stable when MMF was tapered. In conclusion, the use of MMF improved liver function in this patient with steroid-refractory hepatitis induced by immune checkpoint inhibitor administration.

Alcohol Consumption in Concomitant Liver Disease: How Much is Too Much?

Purpose of Review

High consumption of alcohol can lead to cirrhosis. The risk of a low to moderate consumption of alcohol in the setting of a concurrent liver disease is less clear. The aim of this review is to sum the evidence on the risk of adverse outcomes in patients with liver diseases other than alcoholic liver disease who consume alcohol.

Recent Findings

High alcohol consumption is strongly associated with adverse outcomes in most liver diseases. For hepatitis C, some evidence points to an increased risk for fibrosis progression also with low amounts. For non-alcoholic fatty liver disease, most studies indicate an inverse association between fibrosis and alcohol consumption, but methodological limitations reduce inference.

Summary

High alcohol consumption is associated with an increased risk of fibrosis progression and other adverse outcomes, while less is clear regarding low to moderate consumption. Obtaining high-level evidence on this topic ought to be the objective of future studies. Currently, an individual risk profile should be obtained in patients with liver disease who consume alcohol.

The Effects of Alcohol on Other Chronic Liver Diseases

Alcohol consumption is often a comorbid condition in other chronic liver diseases. It has been shown to act in synergy to increase liver injury in viral hepatitis, hereditary hemochromatosis, and nonalcoholic fatty liver disease (NAFLD), leading to an increased risk of cirrhosis, hepatocellular carcinoma, and liver-related mortality. Data suggest that modest alcohol consumption may be inversely related to the risk of developing NAFLD and lower rates of progression of NAFLD to nonalcoholic steatohepatitis (NASH). This article reviews data on the relationship between alcohol consumption and other chronic liver diseases.

National incidence of autoimmune liver diseases and its relationship with the human development index

OBJECTIVE

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), autoimmune hepatitis (AIH) and immunoglobulin G4 related cholangitis represent the major autoimmune liver diseases (AILD). However, the relationship between AILD incidence and socioeconomic development levels is yet to be explored.

RESULTS

A total of 43 studies were included. There was a positive but not significant correlation between the PBC incidence and HDI on a global level (r=0.348, P=0.082). However, in Europe, a significantly positive correlation existed between the PBC incidence and HDI (r=0.455, P=0.044). No statistical correlation between PSC incidence and HDI was observed (r=0.116, P=0.706). The incidence of AIH revealed a positive correlation with the national HDI both globally (r=0.638, P=0.014) and in Europe (r=0.644, P=0.045). Moreover, the PBC incidence demonstrated a positive correlation with the health index (r=0.422, P=0.036), but a negative correlation with the education index (r= -0.650, P<0.01). Moreover, the income index presented a positive correlation with both the PSC incidence (r=0.599, P=0.031) and the AIH incidence (r=0.649, P=0.012).

METHODS

PubMed was searched to identify relevant epidemiological studies on AILD. The human development index (HDI) was applied as an indicator for socioeconomic development. HDI data were obtained and calculated based on the 2014 Human Development Report. Pearson coefficient and linear regression analysis were conducted to estimate the correlation between incidence and HDI.

CONCLUSIONS

There is positive association between the national incidence of AILD and the socioeconomic status, as measured by HDI. In less-developed countries, the incidence of AILD, especially PBC and AIH, might be less common.

Difference in clinical presentation, immunology profile and treatment response of type 1 autoimmune hepatitis between United Kingdom and Singapore patients

Background

Autoimmune hepatitis (AIH) is an immune-mediated liver disease of unknown etiology. Increasing incidence of AIH in Asian patients has been reported. However, the phenotypic difference of Asian patients in Europe and Asia has still not been explored.

Aim

To evaluate the clinical presentation, biochemical and immunological profiles, treatment response and survival outcome of type 1 AIH from two tertiary liver transplant centres (United Kingdom and Singapore).

Method

Patients who fulfilled the simplified diagnostic scoring criteria of AIH were included in the study. Patients with overlap syndrome were excluded.

Results

Totals of 40 Asian patients and 159 Caucasian patients from the University Hospital of Birmingham National Health Service Foundation Trust, UK, were compared with 57 Asian patients from Singapore General Hospital, Singapore. Asian patients from Singapore present significantly much later (median 55 vs. 32 years, p < 0.001), had higher MELD (p < 0.001) with lower albumin (p < 0.001) and higher bilirubin (p < 0.001) and lower ASMA positivity (p < 0.001) at diagnosis compared to UK Asian. Jaundice at presentation was much higher in Singapore Asian patients compared to UK Asian (53 vs. 30 %) but cirrhosis at diagnosis was more common in UK patients. Associated autoimmune conditions were less commonly seen in Singapore Asians. Comparing between UK cohorts, Asian patients present at younger age and have higher IgG level compared to Caucasian. Overall, 5-year transplant-free survival in all three cohorts was similar (p = 0.846).

Conclusion

We demonstrate that AIH patients from Singapore present at older age with jaundice and have a low positivity of SMA. Despite these differences, transplant-free survival is similar in the two groups.

Mechanisms of tissue injury in autoimmune liver diseases

Autoimmune diseases affecting the liver are mainly represented by autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The characteristic morphologic patterns of injury are a chronic hepatitis pattern of damage in AIH, destruction of small intrahepatic bile ducts in PBC and periductal fibrosis and inflammation involving larger bile ducts in PSC. The factors responsible for initiation and perpetuation of the injury in all the three autoimmune liver diseases are not understood completely but are likely to be environmental triggers on the background of genetic variation in immune regulation. In this review, we summarise the current understanding of the mechanisms underlying the breakdown of self-tolerance in autoimmune liver diseases.