Influence of genes, sex, age and environment on the onset of autoimmune hepatitis

Advanced MR imaging for detection of liver fibrosis and inflammation in autoimmune hepatitis: a state-of-the-art review

Autoimmune hepatitis (AIH) is a rare chronic liver disease, associated with a high level of morbidity and high mortality; approximately 40% of patients with severe untreated disease die within 6 months of diagnosis. It should be treated to achieve complete biochemical and histologic resolution of the disease using corticosteroids and immunosuppression to prevent further progression to cirrhosis. The use of invasive liver biopsy is recommended for the staging and assessment of inflammation and fibrosis for treatment decision-making in the face of an unsatisfactory response or clinical remission, including being a determinant for withdrawal of immunosuppression. On the other hand, liver biopsy is invasive, costly, and not free of complications. It also has potential sampling error and poor interobserver agreement. The limitations of liver biopsy highlight the importance of developing new imaging biomarkers that allow accurate and non-invasive assessment of AIH in terms of liver inflammation and fibrosis, developing the virtual biopsy concept. Therefore, we review the state-of-the-art of Magnetic Resonance Imaging (MRI) sequences for the noninvasive evaluation of autoimmune hepatitis, including historical advances and future directions.

Leptin gene Polymorphism and Leptin protein levels in Pediatric Autoimmune Hepatitis

BACKGROUND

Leptin plays a role in regulating energy balance, immunity, and inflammation. Studies suggest higher leptin levels might be associated with various autoimmune diseases. Most of them were in adult. To our knowledge, our study is one of the few that describe serum leptin level and leptin gene polymorphism in children with autoimmune hepatitis (AIH).

OBJECTIVE

Our study aims to explore the association between serum leptin level and genetic variations in leptin gene with the likelihood of AIH in children.

PATIENTS AND METHODS

Thirty-one children with AIH and 29 healthy children serving as a control group were included. Serum leptin levels were measured by ELISA assays. Leptin rs2167270 genotyping was done using the real time-PCR. The relationship of serum leptin level and leptin gene polymorphism with patients' data was studied. Patients follow up to assess treatment response.

RESULTS

Children with AIH had significantly higher levels of leptin compared to healthy controls. GG genotype was significantly more prevalent in the AIH group compared to controls.

CONCLUSION

High serum leptin levels and leptin gene polymorphism may play a role in AIH development. It is worthy to recognize if leptin can serve as diagnostic and/or therapeutic target in AIH in children.

Are Gender Differences Important for Autoimmune Liver Diseases?

Gender Medicine has had an enormous expansion over the last ten years. Autoimmune liver diseases include several conditions, i.e., autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and conditions involving the liver or biliary tree overlapping with AIH, as well as IgG4-related disease. However, little is known about the impact of sex in the pathogenesis and natural history of these conditions. The purpose of this review is to provide an update of the gender disparities among the autoimmune liver diseases by reviewing the data published from 1999 to 2023. The epidemiology of these diseases has been changing over the last years, due to the amelioration of knowledge in their diagnosis, pathogenesis, and treatment. The clinical data collected so far support the existence of sex differences in the natural history of autoimmune liver diseases. Notably, their history could be longer than that which is now known, with problems being initiated even at a pediatric age. Moreover, gender disparity has been observed during the onset of complications related to end-stage liver disease, including cancer incidence. However, there is still an important debate among researchers about the impact of sex and the pathogenesis of these conditions. With this review, we would like to emphasize the urgency of basic science and clinical research to increase our understanding of the sex differences in autoimmune liver diseases.

Overview of hepatocellular carcinoma: from molecular aspects to future therapeutic options

Hepatocellular carcinoma (HCC) is the seventh most highly prevalent malignant tumor globally and the second most common cause of mortality. HCC develops with complex pathways that occur through multistage biological processes. Non-alcoholic fatty liver disease, metabolic-associated fatty liver disease, alcoholic liver disease, autoimmune hepatitis, hepatitis B, and hepatitis C are the causative etiologies of HCC. HCC develops as a result of epigenetic changes, protein-coding gene mutations, and altered signaling pathways. Biomarkers and potential therapeutic targets for HCC open up new possibilities for treating the disease. Immune checkpoint inhibitors are included in the treatment options in combination with molecular targeted therapy.

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.

Type 2 autoimmune hepatitis: Genetic susceptibility

Two types of autoimmune hepatitis (AIH) are recognized; AIH-1 is characterized by the presence of anti-nuclear and/or anti-smooth muscle autoantibodies, while AIH-2 is associated with the presence of anti-Liver kidney microsome and/or anti-Liver Cytosol antibodies. The autoantigens targeted by AIH-2 autoantibodies are the cytochrome P450 2D6 and Formiminotransferase-cyclodeaminase for anti-LKM1 and anti-LC1 respectively. Both autoantigens are expressed in hepatocytes at higher levels than in any other cell type. Therefore, compared to AIH-1, the autoantigens targeted in AIH-2 are predominantly tissue-specific. Distinct clinical features are specific to AIH-2 compared to AIH-1, including diagnosis in younger patients (mean age 6.6 years), onset as fulminant hepatitis in very young patients (3 years of age or less), higher frequency in children than in adults and is frequently associated with extrahepatic T cell-mediated autoimmune diseases. AIH-2 is also often diagnosed in patients with primary immunodeficiency. AIH-2 is associated with specific HLA class II susceptibility alleles; DQB1*0201 is considered the main determinant of susceptibility while DRB1*07/DRB1*03 is associated with the type of autoantibody present. HLA DQB1*0201 is in strong linkage disequilibrium with both HLA DRB1*03 and DRB1*07. Interestingly, as in humans, MHC and non-MHC genes strongly influence the development of the disease in an animal model of AIH-2. Altogether, these findings suggest that AIH-2 incidence is likely dependent on specific genetic susceptibility factors combined with distinct environmental triggers.

Nosocomial infections in female compared with male patients with decompensated liver cirrhosis

There are considerable differences between males and females regarding the etiology, progression and outcome of liver diseases. Infections are a frequent and severe complication in these patients. This study aimed to examine sex specific differences in the incidence and clinical course of nosocomial infections in patients with decompensated liver cirrhosis. A number of 556 consecutive hospitalized patients with decompensated liver cirrhosis and ascites were analyzed. The patients were followed up for the incidence of nosocomial infections, acute kidney injury (AKI), acute-on-chronic liver failure (ACLF) as well as liver transplantation and death (LTx-free survival). A number of 285 patients (111 women and 174 men) developed a nosocomial infection. Incidence was numerically lower in men (P = 0.076). While the frequency of a nosocomial spontaneous bacterial peritonitis was similar between males and females, the incidence of a nosocomial urinary tract infection was significantly higher in women (P < 0.001). No sex specific differences were documented regarding the outcome of an infection as indicated by a similar incidence of, AKI, ACLF as well as LTx-free survival. There seem to be no major differences in the incidence and outcome of nosocomial infections between male and female patients.

Environmental exposure as a risk-modifying factor in liver diseases: Knowns and unknowns

Liver diseases are considered to predominantly possess an inherited or xenobiotic etiology. However, inheritance drives the ability to appropriately adapt to environmental stressors, and disease is the culmination of a maladaptive response. Thus “pure” genetic and “pure” xenobiotic liver diseases are modified by each other and other factors, identified or unknown. The purpose of this review is to highlight the knowledgebase of environmental exposure as a potential risk modifying agent for the development of liver disease by other causes. This exercise is not to argue that all liver diseases have an environmental component, but to challenge the assumption that the current state of our knowledge is sufficient in all cases to conclusively dismiss this as a possibility. This review also discusses key new tools and approaches that will likely be critical to address this question in the future. Taken together, identifying the key gaps in our understanding is critical for the field to move forward, or at the very least to “know what we don't know.”

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.

Autoimmune Hepatitis in Children: Prednisone Plus Azathioprine Versus Cyclosporine: A Randomized Trial

OBJECTIVE

The aim of this study was to find the outcome and adverse effects of 2 initial treatments in children with autoimmune hepatitis, prednisone (PRED) plus azathioprine (AZA) versus cyclosporine (CsA).

STUDY DESIGN

Between December 2008 and February 2012, 50 consecutive patients were centrally randomized to 1 of 2 treatment arms. Group 1: PRED was indicated at a dose of 1 to 2 mg · kg · day (up to 60 mg/day) and AZA at a dose of 1 to 2 mg · kg · day. Group 2: CsA was administered at a dose of 4 mg · kg · day orally divided into 2 doses. After remission, all patients were given a combination of PRED at 0.3 to 0.5 mg · kg · day and AZA at 1 to 2 mg · kg · day. Children presenting liver failure were placed on a triple immunosuppressive regimen if this condition persisted after 1 week of treatment, after liver function normalization they were switched back to their initial scheme.

RESULTS

A total of 26 patients received PRED-AZA and 24 CsA. Both treatments showed similar initial results in effectiveness and safety, although remission was achieved earlier with PRED-AZA: 8.6 versus CsA: 13.6 weeks (P < 0.0081). All children recovered liver function in a mean time of 32 ± 26 days. Cushingoid syndrome was more frequently observed with PRED-AZA (P < 0.001) and gingival hypertrophy with CsA (P < 0.001). A significant increase in body mass index was observed in all patients from initial treatment to remission, being greater with PRED-AZA.

CONCLUSIONS

Similar outcomes were obtained with PRED plus AZA or CsA treatments. Either therapeutic strategy could be used according to the particular characteristics of each patient. Triple immunosuppression was beneficial in patients with liver failure at onset.

Association of Interleukin-6 and Interleukin-1 Family Gene Polymorphisms in Autoimmune Hepatitis

INTRODUCTION AND AIM

Autoimmune hepatitis (AIH) is an immune-mediated destruction of liver cells, in recognition of interface hepatitis, seropositivity for autoantibodies, and interface hepatitis in histology sections. Hepatocyte destruction in AIH is the direct result of CD4+ T-cell destruction. Yet, Th17 mediated immune attach and a diversity of cytokine networks, including pro-inflammatory cytokines such as Interleukin 1 (IL-1) and Interleukin 6 (IL-6), set the stage for the destructive liver damage.

MATERIAL AND METHOD

Peripheral blood samples from 57 patients, with AIH, recruited from referrals to the main pediatric hospital in Tehran. Single nucleotide polymorphisms for the following cytokines genes, were evaluated through, polymerase chain reaction with sequencespecific primers (PCR-SSP) assay: IL-1a (C/T -889), IL-1α (C/T -511), IL-1β (C/T +3962), IL-1 receptor (IL-1R; C/T Pst-I 1970), IL-1RA (C/T Mspa-I 11100), and IL-6 (C/G -174 and A/G nt565).

RESULTS

Significant higher frequency of genotype AA was detected in patients in IL-6 at position nt565 (15.8% in AIH patients vs. 2.9% in controls, p = 0.003). The haplotype GA of IL-6 at -174 and nt565, was significantly overrepresented in the AIH group, compared to (20.9% of AIH vs. 1.4% in controls p < 0.0001).

CONCLUSION

Results of our study, indicate significant deviation toward high yield IL-6 polymorphisms, in AIH patients. These data could bring new insights in pathophysiology of disease, which could contribute to developing novel treatments for AIH.

[Autoimmune hepatitis: Immunological diagnosis]

Autoimmune hepatopathies (AIHT) including autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune cholangitis (AIC), represent an impressive entities in clinical practice. Their pathogenesis is not perfectly elucidated. Several factors are involved in the initiation of hepatic autoimmune and inflammatory phenomena such as genetic predisposition, molecular mimicry and/or abnormalities of T-regulatory lymphocytes. AIHT have a wide spectrum of presentation, ranging from asymptomatic forms to severe acute liver failure. The diagnosis of AIHT is based on the presence of hyperglobulinemia, cytolysis, cholestasis, typical even specific circulating auto-antibodies, distinctive of AIH or PBC, and histological abnormalities as well as necrosis and inflammation. Anti-F actin, anti-LKM1, anti-LC1 antibodies permit to distinguish between AIH type 1 and AIH type 2. Anti-SLA/LP antibodies are rather associated to more severe hepatitis, and particularly useful for the diagnosis of seronegative AIH for other the antibodies. Due to the relevant diagnostic value of anti-M2, anti-Sp100, and anti-gp210 antibodies, the diagnosis of PBC is more affordable than that of PSC and AIC. Based on clinical data, the immunological diagnosis of AIHT takes advantage of the various specialized laboratory techniques including immunofluorescence, immunodot or blot, and the Elisa systems, provided of a closer collaboration between the biologist and the physician.

Hyperferritinemia and hypergammaglobulinemia predict the treatment response to standard therapy in autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic hepatitis with an increasing incidence. The majority of patients require life-long immunosuppression and incomplete treatment response is associated with a disease progression. An abnormal iron homeostasis or hyperferritinemia is associated with worse outcome in other chronic liver diseases and after liver transplantation. We assessed the capacity of baseline parameters including the iron status to predict the treatment response upon standard therapy in 109 patients with untreated AIH type 1 (AIH-1) in a retrospective single center study. Thereby, a hyperferritinemia (> 2.09 times upper limit of normal; Odds ratio (OR) = 8.82; 95% confidence interval (CI): 2.25–34.52) and lower immunoglobulins (<1.89 times upper limit of normal; OR = 6.78; CI: 1.87–24.59) at baseline were independently associated with the achievement of complete biochemical remission upon standard therapy. The predictive value increased when both variables were combined to a single treatment response score, when the cohort was randomly split into a training (area under the curve (AUC) = 0.749; CI 0.635–0.863) and internal validation cohort (AUC = 0.741; CI 0.558–0.924). Patients with a low treatment response score (<1) had significantly higher cumulative remission rates in the training (p<0.001) and the validation cohort (p = 0.024). The baseline hyperferritinemia was accompanied by a high serum iron, elevated transferrin saturations and mild hepatic iron depositions in the majority of patients. However, the abnormal iron status was quickly reversible under therapy. Mechanistically, the iron parameters were not stringently related to a hepatocellular damage. Ferritin rather seems deregulated from the master regulator hepcidin, which was down regulated, potentially mediated by the elevated hepatocyte growth factor. In conclusion, baseline levels of serum ferritin and immunoglobulins, which are part of the diagnostic work-up of AIH, can be used to predict the treatment response upon standard therapy in AIH-1, although confirmation from larger multicenter studies is pending.

IL4 gene polymorphisms in Iranian patients with autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis (AIH) is a chronic long-lasting hepatocellular inflammation associated with circulating auto antibodies. In addition to the genetic component, several cytokines have been implicated to be involved in AIH. This study was performed to investigate potential associations of AIH with IL4 gene variants.

METHOD

The studied alleles and genotypes included: IL4G/T allele polymorphisms at position -1098 and C/T allele polymorphisms at two positions (-33 and -590) on the IL4 gene, in addition to the A/G allele polymorphisms at position +1902 on the IL4RA gene.

RESULT

The IL4 C allele and CC genotype at position -590 and TT genotype at position -33 had a significantly higher frequency in AIH patients.

CONCLUSION

This study identified the IL4 C allele and CC genotype susceptibility gene in AIH, which will provide better insights into the mechanisms of AIH and potential therapeutic interventions.

Dysfunction of phagocytosis and lysosome activities of intraperitoneal macrophages in autoimmune hepatitis mice

AIM: To evaluate the phagocytic function and lysosome activities of intraperitoneal macrophages in autoimmune hepatitis (AIH) mice.

METHODS: Eighty C57BL/680 mice were divided into an AIH group and a control group. AIH was induced by intraperitoneal injection of liver-specific antigen S-100 and Freund's complete adjuvant. Intraperitoneal macrophages were obtained through peritoneal washing. Macrophages were co-cultured with fluorescein isothiocyanate (FITC) labeled Escherichia coli (E. coli) and lysotracker red. The phagocytic rate/index and lysotracker fluorescence intensities were analyzed by fluorescence microscopy or flow cytometry.

RESULTS: Both the phagocytic rate (24.07% ± 10.21% vs 47.27% ± 15.57%, t = -7.899, P < 0.05) and index (0.36 ± 0.19 vs 0.89 ± 0.34, t = -6.793, P < 0.05) of macrophages from AIH mice were lower than those from control mice. Most of FITC-labeled E. coli bacteria were transported into lysosomes after phagocytosis, which enhanced the activities of lysosomes. No matter before or after co-culture with FITC-labeled E. coli, the activities of lysosome in the AIH group were less than those of control mice (before co-culture: 5.85 ± 0.35 vs 15.39 ± 0.72, t = -5.296, P < 0.05; after co-culture: 9.45 ± 0.84 vs 30.00 ± 1.36, t = -7.889, P < 0.05).

CONCLUSION: The phagocytic and lysosome functions of macrophages in AIH mice are reduced, which may be pathogenic factors in AIH.

HLA-DRB1 alleles of susceptibility and protection in Iranians with autoimmune hepatitis

Autoimmune hepatitis (AIH) is an uncommon autoimmune liver disease of unknown etiology. The aim of this study was to determine the frequency of HLA-DRB1 alleles in Iranian patients with AIH and investigate the association between HLA alleles and the different types of the disease. Fifty-four AIH patients and 100 age- and sex-matched healthy controls were subjected to low resolution HLA-DRB typing performed by polymerase chain reaction-sequence-specific primers (PCR-SSP) technique. The results revealed higher frequencies of HLA-DRB1(∗)03, and DRB1(∗)13 alleles in patients with AIH compared to controls. However, DRB1(∗)11 was less frequent in AIH patients. In type I AIH patients HLA-DRB1(∗)03, HLA-DRB1(∗)04, HLA-DRB1(∗)08, and HLA-DRB1(∗)13 were the most frequent alleles. While in type II, the most frequent alleles were HLA-DRB1(∗)07 and HLA-DRB1(∗)13. The seronegative patients showed more frequency of HLA-DRB1(∗)03 and HLA-DRB3. In contrary, the frequency of HLA-DRB1(∗)11, HLA-DRB1(∗)15 and HLA-DRB5 in type 1 was less than healthy individuals. These findings indicate the role of HLA-DRB haplotypes in AIH susceptibility and protection, in the Iranian population.

A molecular marker of disease activity in autoimmune liver diseases with histopathological correlation; FoXp3/RORγt ratio

Autoimmune liver diseases (AILDs) encompass a group of diseases with variable clinicopathological manifestations. Th17 and Treg cells have roles in the pathogenesis of AILDs with a balance shifted towards a relative increase in activity of the Th17 cells. In this study, the balance between the transcription factors of Treg and Th17 cells (FoXp3 and RORγt) was sought as a molecular marker of disease activity and to highlight the pathogenesis. The peripheral blood samples of 46 treatment-naive patients were collected and RNA was extracted. Real time PCR was performed and the ratio of gene expression was calculated. Histopathology of 18 patients was obtained and the activity score of these biopsies were also corroborated with their respective molecular (FoXp3/RORγt) (FRGT=FoXp3-ROR Gamma T) ratio. The FRGT ratio in healthy individuals was close to 1 and in disease the ratio changed significantly. This ratio (FRGT) was not significantly different in different varieties of AILD or in adult or paediatric form of the disease. However, the ratio remained consistently below 1 (mean 0.3) in acute disease and high (mean 224.7) in chronic or asymptomatic form of the disease (p < 0.001). The histopathological activity score also significantly correlated with the ratio. This signified the relative excess of Th17 (RORγt) in active disease as compared to Treg (FoXp3) and the reverse in chronic form. This ratio can be an important peripheral molecular marker to assess the disease activity without the necessity of performing a liver biopsy.

Regulatory T Cells in Autoimmune and Viral Chronic Hepatitis

In both autoimmune liver disease and chronic viral hepatitis, the injury results from an immune-mediated cytotoxic T cell response to liver cells. As such, it is not surprising that CD4(+) regulatory T cells, a key regulatory population of T cells able to curb immune responses, could be involved in both autoimmune hepatitis and chronic viral hepatitis. The liver can induce the conversion of naïve CD4(+) T cells to CD4(+) regulatory T cells and induce tolerance to locally expressed antigens. This tolerance mechanism is carefully regulated in physiological conditions but any imbalance could be pathological. An overly tolerant immune response can lead to chronic infections while an overreactive and unbridled immune response can lead to autoimmune hepatitis. With the recent advent of monoclonal antibodies able to target regulatory T cells (daclizumab) and improve immune responses and several ongoing clinical trials analysing the impact of regulatory T cell infusion on autoimmune liver disease or liver transplant tolerance, modulation of immunological tolerance through CD4(+) regulatory T cells could be a key element of future immunotherapies for several liver diseases allowing restoring the balance between proper immune responses and tolerance.  .

Divergent effects of RIP1 or RIP3 blockade in murine models of acute liver injury

Necroptosis is a recently described Caspase 8-independent method of cell death that denotes organized cellular necrosis. The roles of RIP1 and RIP3 in mediating hepatocyte death from acute liver injury are incompletely defined. Effects of necroptosis blockade were studied by separately targeting RIP1 and RIP3 in diverse murine models of acute liver injury. Blockade of necroptosis had disparate effects on disease outcome depending on the precise etiology of liver injury and component of the necrosome targeted. In ConA-induced autoimmune hepatitis, RIP3 deletion was protective, whereas RIP1 inhibition exacerbated disease, accelerated animal death, and was associated with increased hepatocyte apoptosis. Conversely, in acetaminophen-mediated liver injury, blockade of either RIP1 or RIP3 was protective and was associated with lower NLRP3 inflammasome activation. Our work highlights the fact that diverse modes of acute liver injury have differing requirements for RIP1 and RIP3; moreover, within a single injury model, RIP1 and RIP3 blockade can have diametrically opposite effects on tissue damage, suggesting that interference with distinct components of the necrosome must be considered separately.

Clinical features of autoimmune hepatitis in patients positive for hepatitis B virus markers

AIM: To investigate the clinical, biochemical and immunological characteristics and prognosis of autoimmune hepatitis (AIH) in patients positive for hepatitis B virus (HBV) markers.

METHODS: Fifty-four AIH patients were enrolled in the study, including 30 who were positive for hepatitis B virus markers (group A) and 24 who were negative for hepatitis B virus markers (group B). The clinical, biochemical and immunological characteristics and prognosis were compared between the two groups.

RESULTS: The age and symptoms were similar between the two groups. The majority of patients in the two groups were elderly females. Liver enzyme elevation was the main symptom in nearly half of the patients. More than 85% of the patients in group A were positive for HBV-related antibodies. The percentages of patients with cirrhosis, esophageal variceal bleeding, hypoalbuminemia, high ANA titer and poor prognosis in group A were 86.7%, 40.0%, 70.0%, 86.7%, and 33.3%, respectively, while the corresponding percentages in group B were 54.2%, 4.2%, 33.3%, 45.9% and 8.3%. The percentages of patients with elevated IgG level and positive anti-SSA/SSB in group A were 38.5% and 3.3%, respectively, and the corresponding values were 66.7% and 25.0% in group B.

CONCLUSION: AIH patients positive for HBV markers are mostly elderly females and positive for HBV-related antibodies. Liver enzyme elevation is the main symptom. Cirrhosis, decompensation and poor prognosis are more popular in AIH patients with HBV infection than without.

Adoptive transfer of ex vivo expanded regulatory T cells in an autoimmune hepatitis murine model restores peripheral tolerance

Autoimmune hepatitis (AIH) is characterized by a loss of immunological tolerance to hepatocytes. Patients respond well to immunosuppression but progression to endstage liver disease occurs in 10%-20% of cases, leading to liver transplantation. Using a murine model of type 2 AIH, we identified susceptibility factors for autoimmune hepatitis and attempted to restore immunological tolerance to liver autoantigens. An increased ectopic expression of a liver autoantigen (FTCD) in the thymus leading to reduced numbers of circulating autoreactive T cells was sufficient to prevent development of AIH in mice. However, in the presence of a reduced central tolerance to FTCD, a strong regulatory T-cell response was able to inhibit proliferation of liver-specific autoreactive T cells and prevent AIH. Development of a severe AIH stemmed from reduced numbers of functional regulatory T cell (Tregs) leading to an increased proliferation of FTCD-specific autoreactive T and B cells. Adoptive transfer of ex vivo expanded CXCR3(+) Tregs in mice with AIH efficiently targeted the inflamed liver, restored peripheral tolerance to FTCD, and induced remission of AIH.

CONCLUSION

Peripheral tolerance to liver autoantigens in AIH is paramount. Autologous infusion of ex vivo expanded CXCR3(+) Tregs in AIH patients could be an effective therapeutic approach to restore peripheral tolerance and induce remission of AIH.

Liver restores immune homeostasis after local inflammation despite the presence of autoreactive T cells

The liver must keep equilibrium between immune tolerance and immunity in order to protect itself from pathogens while maintaining tolerance to food antigens. An imbalance between these two states could result in an inflammatory liver disease. The aims of this study were to identify factors responsible for a break of tolerance and characterize the subsequent restoration of liver immune homeostasis. A pro-inflammatory environment was created in the liver by the co-administration of TLR ligands CpG and Poly(I:C) in presence or absence of activated liver-specific autoreactive CD8(+) T cells. Regardless of autoreactive CD8(+) T cells, mice injected with CpG and Poly(I:C) showed elevated serum ALT levels and a transient liver inflammation. Both CpG/Poly(I:C) and autoreactive CD8(+)T cells induced expression of TLR9 and INF-γ by the liver, and an up-regulation of homing and adhesion molecules CXCL9, CXCL10, CXCL16, ICAM-1 and VCAM-1. Transferred CFSE-labeled autoreactive CD8(+) T cells, in presence of TLR3 and 9 ligands, were recruited by the liver and spleen and proliferated. This population then contracted by apoptosis through intrinsic and extrinsic pathways. Up-regulation of FasL and PD-L1 in the liver was observed. In conclusion, TLR-mediated activation of the innate immune system results in a pro-inflammatory environment that promotes the recruitment of lymphocytes resulting in bystander hepatitis. Despite this pro-inflammatory environment, the presence of autoreactive CD8(+) T cells is not sufficient to sustain an autoimmune response against the liver and immune homeostasis is rapidly restored through the apoptosis of T cells.

Different sites of xenoantigen delivery lead to a virally induced late-onset hepatitis in mice through molecular mimicry

BACKGROUND

Epidemiological and laboratory evidences led to the hypothesis that molecular mimicry between viruses and self-proteins could be linked to the onset of autoimmune hepatitis (AIH). Hepatotropic viruses could be good candidates, as a pro-inflammatory environment may facilitate the development of AIH.

AIMS

The aims of this study were to test a virus ability to induce an AIH through molecular mimicry and the influence of hepatic inflammation in this process.

METHODS

C57BL/6 mice were injected i.v. or i.m. with recombinant adenoviral vectors (RecAdV) encoding for human type 2 AIH antigens to target xenoantigens expression in the liver and to create a transient hepatitis (i.v.) or for 'peripheral' xenoantigens expression (i.m.). Liver injury and B-cell response were evaluated.

RESULTS

Late-onset hepatitis was observed 8 months after i.v. or i.m. RecAdV injections, despite presence or absence of an initial transient hepatitis. Intensity of B-cell response was similar for both type of injections, but the Ig isotypes produced were different. B-cell autoimmune response spread to several liver proteins.

CONCLUSIONS

Liver autoimmune response can be initiated using molecular mimicry over a long period of time, validating the hit-and-run hypothesis. Initial liver inflammatory injury is neither necessary, nor detrimental to the development of AIH. These results highlight the significance of initial events on the pathogenesis of autoimmune liver injury.

Performance of the international classifications criteria for autoimmune hepatitis diagnosis in Mexican patients

The revised score of the International Autoimmune Hepatitis Group (R-IAIHG) and the simplified criteria (SC) are used for diagnosis of autoimmune hepatitis (AIH). Our aim is to evaluate the performance of these classifications to differentiate AIH from other autoimmune liver diseases. The frequency of diagnosis of definite AIH was similar both by the R-IAIHG and the SC systems (41% versus 40%), whereas diagnosis of probable AIH was made more commonly by the R-IAIHG than the SC (59% versus 29%), and 23 patients that have been graded as definite (n = 7) or probable (n = 16) AIH by the R-IAIHG had non-diagnostic scores by the SC system. The scoring systems rendered concordant diagnosis of definite (n = 15) and probable (n = 13) AIH in 28/73 patients (38%). Discordant diagnoses of AIH were rendered in 45/73 patients (62%). The R-IAIHG exhibited a sensitivity of 95%, specificity of 90%, and positive predictive value (PPV) and negative predictive value (NPV) of 93% for both. On the other hand, the SC had a lower sensitivity (65%) but a higher specificity (100%), PPV of 100%, and NPV of 68%. In conclusion, both international scoring systems diagnosed the same number of cases as definite AIH. The R-IAIHG showed a higher sensitivity in diagnosing AIH, whereas the SC showed a higher specificity. SC are easier to apply at the bedside and exclude more patients that could have a different etiology.

Autoimmune hepatitis-like disease in C57BL/6 mice infected with mouse hepatitis virus A59

Mouse hepatitis virus A59 (MHV A59) induces autoantibodies (autoAb) to fumarylacetoacetate hydrolase (FAH), a soluble cytosolic enzyme present in the liver and kidneys, in various mouse strains. The aim of this work was to amplify and diversify the autoimmune response restricted to FAH through the use of the exogenous adjuvant called PADRE. Accordingly, C57BL/6 mice were chosen, because these animals respond to PADRE better than other mouse strains. Results presented herein indicate that, surprisingly, C57BL/6 mice developed signs of autoimmune hepatitis-like disease (AIH), including transient hypergammaglobulinemia, elevated transaminases, autoAb directed against different liver proteins and hepatic cellular infiltrates, indicating that a new model of experimental AIH could be generated by a viral inoculation. Furthermore, PADRE administration amplified the MHV effect, extending the duration of hypergammaglobulinemia and increasing the binding of autoAb as well as the degree of hepatic infiltrates. However, the adjuvant did not expand the time of the symptoms. Additionally, since plasmatic uric acid and high-mobility group box protein 1 (HGMB1) concentrations augmented in MHV- and/or PADRE-treated mice, it is suggested that both alarmins were probably involved in the spreading of the immune response induced by the viral infection and the adjuvant administration.

Case of primary biliary cirrhosis-autoimmune hepatitis overlap which manifested after delivery

A 34-year-old woman showed liver dysfunction for the first time at 3 months after delivery. Two years later, she was referred to our department with continued liver dysfunction. She fulfilled the criteria for primary biliary cirrhosis (PBC)-autoimmune hepatitis (AIH) overlap. Liver dysfunction improved after administration of ursodeoxycholic acid and bezafibrate. To the best of our knowledge this represents the second report of PBC-AIH overlap after delivery and we discuss immunological changes during the perinatal period.

Preventive effects of 1,25-(OH)2VD3 against ConA-induced mouse hepatitis through promoting vitamin D receptor gene expression

AIM

To investigate the immunosuppressive effects of 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)VD(3)) on concanavalin A (ConA)-induced hepatitis and elucidate the action mechanism.

METHODS

Female BALB/C mice were intravenously administered ConA (20 mg/kg) to induce acute immunological liver injury. Liver damage was evaluated in respect to serum alanine transaminase (ALT) level and liver histological changes. The proliferation of splenocytes was measured by using [(3)H]-thymidine incorporation. The cytokine level in the cultured splenocyte supernatant was determined by using enzyme-linked immunosorbent assays (ELISAs). The percentage of different splenic T cell subtypes was analyzed by using flow cytometry. The expression of splenic vitamin D receptor (VDR) mRNA and protein was detected by using real-time qRT-PCR and Western blot, respectively.

RESULTS

1,25-(OH)(2)VD(3) (2.5 microg/kg, ip) significantly decreased the serum ALT levels and markedly attenuated the histological liver damage. The beneficial effect of 1,25-(OH)(2)VD(3) was associated with: (i) inhibition of CD4(+) T cell activation; (ii) reduction of interferon-gamma (IFN-gamma) and elevation of both IL-4 and IL-5 in supernatants of cultured splenocytes; and (iii) elimination of activated T cells by increasing VDR mRNA and protein expression in the spleen.

CONCLUSION

1,25-(OH)(2)VD(3) had a significant protective effect against ConA-induced hepatitis, and its mechanism of action was associated with down-regulation of T cell-mediated immunity and up-regulation of VDR gene expression.

Risk of HCC: genetic heterogeneity and complex genetics

Hepatocellular carcinoma (HCC) is a common form of cancer that arises from hepatocytes and whose risk may be affected by several known environmental factors, including hepatitis viruses, alcohol, cigarette smoking, and others. Rare monogenic syndromes, such as alpha1-antitrypsin deficiency, glycogen storage disease type I, hemochromatosis, acute intermittent and cutanea tarda porphyria, as well as hereditary tyrosinemia type I are associated with a high risk of HCC. Several common conditions or diseases inherited as polygenic traits e.g. autoimmune hepatitis, type 2 diabetes, a family history of HCC, hypothyroidism, and non-alcoholic steatohepatitis also show an increased risk of HCC compared to the general population. Overall, the genetic susceptibility to HCC is characterized by a genetic heterogeneity; a high individual risk of HCC may thus be caused by several unlinked single gene defects, whose carriers are rare in the general population, or by more common conditions inherited by complex genetics.