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A diet rich in saturated fat and carbohydrates causes low-grade chronic inflammation in several organs, including the liver, ultimately driving nonalcoholic steatohepatitis. In this setting, environment-driven lipotoxicity and glucotoxicity induce liver damage, which promotes dendritic cell activation and generates a major histocompatibility complex class II (MHC-II) immunopeptidome enriched with peptides derived from proteins involved in cellular metabolism, oxidative phosphorylation, and the stress responses. Here, we demonstrated that lipotoxicity and glucotoxicity, as driven by a high-fat and high-fructose (HFHF) diet, promoted MHC-II presentation of nested T and B cell epitopes from protein disulfide isomerase family A member 3 (PDIA3), which is involved in immunogenic cell death. Increased MHC-II presentation of PDIA3 peptides was associated with antigen-specific proliferation of hepatic CD4 + immune infiltrates and isotype switch of anti-PDIA3 antibodies from IgM to IgG3, indicative of cellular and humoral PDIA3 autoreactivity. Passive transfer of PDIA3-specific T cells or PDIA3-specific antibodies also exacerbated hepatocyte death, as determined by increased hepatic transaminases detected in the sera of mice subjected to an HFHF but not control diet. Increased humoral responses to PDIA3 were also observed in patients with chronic inflammatory liver conditions, including autoimmune hepatitis, primary biliary cholangitis, and type 2 diabetes. Together, our data indicated that metabolic insults caused by an HFHF diet elicited liver damage and promoted pathogenic immune autoreactivity driven by T and B cell PDIA3 epitopes.

Background and Aims: The "gut homing" hypothesis suggests the pathogenesis of primary sclerosing cholangitis (PSC) is driven by aberrant hepatic expression of gut adhesion molecules and subsequent recruitment of gut-derived T cells to the liver. However, inconsistencies lie within this theory including an absence of investigations and comparisons with other chronic liver diseases (CLD). Here, we examine "the gut homing theory" in patients with PSC with associated inflammatory bowel disease (PSC-IBD) and across multiple inflammatory liver diseases., Approach and Results: Expression of MAdCAM-1, CCL25, and E-Cadherin were assessed histologically and using RT-PCR on explanted liver tissue from patients with CLD undergoing OLT and in normal liver. Liver mononuclear cells were isolated from explanted tissue samples and the expression of gut homing integrins and cytokines on hepatic infiltrating gut-derived T cells was assessed using flow cytometry. Hepatic expression of MAdCAM-1, CCL25 and E-Cadherin was up-regulated in all CLDs compared with normal liver. There were no differences between disease groups. Frequencies of α4β7, αEβ7, CCR9, and GPR15 expressing hepatic T cells was increased in PSC-IBD, but also in CLD controls, compared with normal liver. β7 expressing hepatic T cells displayed an increased inflammatory phenotype compared with β7 negative cells, although this inflammatory cytokine profile was present in both the inflamed and normal liver., Conclusions: These findings refute the widely accepted "gut homing" hypothesis as the primary driver of PSC and indicate that aberrant hepatic recruitment of gut-derived T cells is not unique to PSC, but is a panetiological feature of CLD., (© 2021 American Association for the Study of Liver Diseases.)

Primary Biliary Cholangitis (PBC) is an uncommon, chronic, cholangiopathy of autoimmune origin and unknown etiology characterized by positive anti-mitochondrial autoantibodies (AMA), female preponderance and progression to cirrhosis if left untreated. The diagnosis is based on AMA- or PBC-specific anti-nuclear antibody (ANA)-positivity in the presence of a cholestatic biochemical profile, histologic confirmation being mandatory only in seronegative cases. First-line treatment is ursodeoxycholic acid (UDCA), which is effective in preventing disease progression in about two thirds of the patients. The only approved second-line treatment is obeticholic acid. This article summarizes the most relevant conclusions of a meeting held in Lugano, Switzerland, from September 23rd-25th 2018, gathering basic and clinical scientists with various background from around the world to discuss the latest advances in PBC research. The meeting was dedicated to Ian Mackay, pioneer in the field of autoimmune liver diseases. The role of liver histology needs to be reconsidered: liver pathology consistent with PBC in AMA-positive individuals without biochemical cholestasis is increasingly reported, raising the question as to whether biochemical cholestasis is a reliable disease marker for both clinical practice and trials. The urgent need for new biomarkers, including more accurate markers of cholestasis, was also widely discussed during the meeting. Moreover, new insights in interactions of bile acids with biliary epithelia in PBC provide solid evidence of a role for impaired epithelial protection against potentially toxic hydrophobic bile acids, raising the fundamental question as to whether this bile acid-induced epithelial damage is the cause or the consequence of the autoimmune attack to the biliary epithelium. Strategies are needed to identify difficult-to-treat patients at an early disease stage, when new therapeutic approaches targeting immunologic pathways, in addition to bile acid-based therapies, may be effective. In conclusion, using interdisciplinary approaches, groundbreaking advances can be expected before long in respect to our understanding of the etiopathogenesis of PBC, with the ultimate aim of improving its treatment., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background and Aims: Chronic hepatitis C virus (HCV) infection is associated with a wide range of immunopathological manifestations, which are significantly improved by successful interferon-based treatment. There is paucity of data on the impact of interferon-free HCV clearance on immunopathological manifestations, which might be expected to disappear more frequently as compared to what reported in interferon-induced HCV-clearance. We have investigated liver autoimmune serology before and after interferon-free clearance of HCV by treatment with direct acting antiviral agents (DAA)., Method: Patients within the Swiss Hepatitis C Cohort Study who underwent successful (SVR 12) HCV treatment with DAA were tested for autoimmune liver serology according to dedicated guidelines before and at least 6 months after end of treatment., Results: A total of 235 patients were included; 62% males; median age 56 years; 27% with cirrhosis. Median time between end of DAA treatment and post-treatment serum sampling was 17 months. At least one autoantibody before treatment was found in 175 (74%) patients ; 32 (14%) were positive for 2 autoantibodies; no patient was positive for anti-SLA, anti-LC1 or typical AMA before or after DAA. ANA disappeared in 34%, SMA in 52% and anti-LKM1 in one of two patients after successful treatment, but, unexpectedly, one or more autoantibodies appeared in 27% of pre-treatment negative subjects., Conclusion: HCV clearance by DAA is associated with autoantibody disappearance in more than one third of the patients who were positive before treatment. However, the majority of the patients remain autoantibody-positive and 27% of those who were negative before treatment developed autoantibodies after DAA-induced HCV clearance. These data confirm that HCV infection is associated with autoimmunity and show that the autoimmune imprint persists after viral clearance by DAA, suggesting that long-term follow-up may be warranted., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Autoimmune serology is key to the diagnosis and management of autoimmune liver diseases. Its correct use in clinical practice requires a basic knowledge of the laboratory techniques used for autoantibody detection. Indirect immunofluorescence (IIF) on triple rodent tissue is still the gold standard screening procedure for liver-relevant autoantibodies, while HEp2 cells and human ethanol-fixed neutrophils are used as substrates to characterize nuclear reactivities and to detect anti-neutrophil cytoplasm antibody, respectively. Assays based on purified or recombinant antigens are increasingly used, having the main advantage of being observer-independent and the disadvantage of detecting only autoantibodies whose antigenic target has been identified. The AIH-specific anti-soluble liver antigen antibody cannot be detected by IIF and a molecular-based assay should be used at the screening level. Since autoantibodies may be present in the context of viral hepatitides and other inflammatory liver diseases it is important to exclude these conditions before diagnosing autoimmune liver disease. Anti-nuclear antibody (ANA), most often with a homogeneous IIF pattern on HEp2 cells, characterizes type 1 autoimmune hepatitis (AIH), and is found in association with anti-smooth muscle antibody in about half of the cases. Two IIF ANA patterns are specific for primary biliary cholangitis, namely the rim-like/membranous pattern, and the multiple nuclear dots pattern. Anti-liver kidney microsomal antibody type 1 is the serological hallmark of type 2 AIH, often in association with anti-liver cytosol type 1 antibody. Atypical perinuclear anti-neutrophil antibody, referred to as perinuclear anti-neutrophil nuclear antibody, is frequently detected in primary sclerosing cholangitis, in AIH type 1 and in inflammatory bowel diseases. The anti-asiaglycoprotein receptor antibody is liver-specific but not disease-specific, and reliable commercial assays for its detection are lacking. Anti-mitochondrial antibody is the hallmark of primary biliary cholangitis (PBC), being disease-specific and present in about 95% of the PBC patients. Its incidental detection presages the future development of PBC., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Juvenile sclerosing cholangitis is a rare chronic hepatobiliary disorder characterized by inflammation of the intra- and/or extrahepatic bile ducts, bile duct dilatation, narrowing and obliteration, and, histologically, by inflammatory bile duct damage leading to periductular fibrosis. The diagnosis is based on endoscopic retrograde cholangiopancreatography or magnetic resonance cholangiopancreatography. In children, it may be associated to a variety of systemic and hepatic conditions: thus, the term "primary" sclerosing cholangitis should be reserved for the rare cases without a known cause. Small duct disease is diagnosed in the presence of histological features diagnostic of sclerosing cholangitis and normal cholangiography. Autoimmune sclerosing cholangitis (ASC) is a form of sclerosing cholangitis with strong autoimmune features overlapping with those of autoimmune hepatitis (AIH). It is a well-recognized nosological entity in paediatrics, where it accounts for the majority of sclerosing cholangitis cases. It is as prevalent as AIH in children, is equally frequent in males and females, half of the patients have concomitant inflammatory bowel disease, virtually all patients have raised immunoglobulin G levels and positive anti-nuclear and/or anti-smooth muscle antibodies. Half of the ASC patients respond well to standard immunosuppressive treatment for AIH with the addition of ursodeoxycholic acid, but the transplant rate is higher than in AIH, and post-transplant recurrence is frequent. A number of open questions remain: are ASC and AIH distinct entities or different manifestations of the same condition? What is the role of histology? Is small duct disease a specific entity? What is the relationship between ASC and adult primary sclerosing cholangitis? What is the role of inflammatory bowel disease? In addition, validated diagnostic criteria for ASC are needed., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

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

Autoimmune hepatitis (AIH) is a severe liver disease affecting all age groups worldwide. Novel basic and clinical aspects of AIH, addressed at a Monothematic Conference in London in September 2015, are highlighted in this review. The diagnosis of AIH relies upon detection of characteristic autoantibodies, hypergammaglobulinemia, and interface hepatitis on liver histology. The International Autoimmune Hepatitis Group (IAIHG) has devised diagnostic scoring systems to help in comparative studies and clinical practice. AIH arises in a genetically predisposed host, when yet unknown triggers - such an encounter with a pathogen - lead to a T cell-mediated immune response targeting liver autoantigens. This immune response is inadequately controlled because regulatory mechanisms are impaired. The mainstay of treatment for AIH is immunosuppression, which should be instituted as soon as the diagnosis is made. Standard treatment regimens include relatively high doses of predniso(lo)ne, which are tapered gradually as azathioprine is introduced. Recent guidelines have described newer treatment regimens and have tightened the goal of therapy to complete normalization of biochemical, serological and histological parameters. Mycophenolate mofetil, calcineurin inhibitors, mTOR inhibitors and biological agents are potential salvage therapies, but should be reserved for selected non-responsive patients and administered only in experienced centers. Liver transplantation is a life-saving option for those patients who progress to end-stage liver disease. Further dissection of cellular and molecular pathways involved in AIH pathogenesis is likely to lead to the discovery of novel, tailored and better tolerated therapies., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Biliary atresia (BA), a cholangiopathy of unknown etiology is associated with intrahepatic mononuclear cell infiltrate. An abnormal reaction to viral exposure has been hypothesized in some cases. We aimed to investigate the nature of the CD4+ hepatic infiltrate in defined clinical variants of BA by quantification of inflammatory cell components., Methods: Liver biopsies of infants obtained at Kasai portoenterostomy (KPE) were stained immunohistochemically using monoclonal antibodies to Tbet, GATA-3, FOXP3 and interleukin (IL) 17, identifying Th-1, Th-2, Tregs and Th-17 cells respectively. T cells were counted with the aid of a graticule. Data are reported as median (range) of cells per high-power-field (×400) and compared using nonparametric statistical tests with P≤0.05 regarded as significant., Results: Liver biopsies from BA (n=37) and age-matched cholestatic controls (e.g. alpha-1-anti trypsin deficiency, Alagilles syndrome, n=12) were investigated. BA infants were divided into three groups: cytomegalovirus IgM +ve (CMV; n=9); BA splenic malformation (BASM; n=9) and isolated BA (IBA; n=19). All T-cell subsets were present in the portal tracts, with an overrepresentation of Th-1 (P<0.001) and Th-17 (P<0.03), but not Th-2 (P=0.94) or Tregs (P=0.15), compared to controls. Th-1 cells predominated in the CMV group; (18 [7-37] vs. 3 [0-14] [BASM] and vs. 5 [3-23] [IBA]; P<0.01 both), while no subgroup differences were seen for Th-17 cells. The degree of Th-1 cell infiltrate inversely correlated with platelet count (rS=-0.49; P<0.01). Th-17 cells were fewer (6 [2-11] vs. 11 [8-20]; P=0.02) in infants who cleared their jaundice (n=15, <20μmol/L) although this did not translate to improved native liver survival (P=0.17)., Conclusions: Th-17 cells infiltrate the liver in BA and are associated with a worse surgical outcome; a Th-1 profile predominates in CMV-associated BA., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Autoimmune liver disorders in childhood include autoimmune hepatitis (AIH) and AIH/sclerosing cholangitis overlap syndrome (henceforth referred to as autoimmune sclerosing cholangitis, ASC). These inflammatory liver disorders are characterised histologically by interface hepatitis, biochemically by elevated transaminase levels, and serologically by autoantibodies and increased levels of immunoglobulin G. AIH is particularly aggressive in children and progresses rapidly unless immunosuppressive treatment is started promptly. With appropriate treatment, 80% of patients achieve remission and long-term survival. For non-responders and difficult-to-treat patients, novel and more effective therapeutic approaches are sought. ASC responds to the same treatment used for AIH in regards to parenchymal inflammation, but bile duct disease progresses in about 50% of cases, leading to a worse prognosis and a higher liver transplantation requirement; moreover, it has a high recurrence rate after transplant. Progression of liver disease and recurrence after transplant are more common in patients with associated poorly controlled inflammatory bowel disease. Though the mechanisms underlying the pathogenesis of liver autoimmunity are not fully understood, genetic and environmental factors are likely to be involved. A deeper understanding of the pathogenesis of these conditions will contribute to the development of novel treatments, aimed ultimately at the restoration of tolerance to liver-derived antigens.

Autoimmune hepatitis (AIH) is an immune-mediated liver disorder characterised by female preponderance, elevated transaminase and immunoglobulin G levels, seropositivity for autoantibodies and interface hepatitis. Presentation is highly variable, therefore AIH should be considered during the diagnostic workup of any increase in liver enzyme levels. Overlap/variant forms of the disease, presenting with concomitant features of primary biliary cirrhosis or primary sclerosing cholangitis are increasingly recognised. AIH is exquisitely responsive to immunosuppressive treatment, which should be instituted promptly to prevent rapid deterioration and promote remission and long-term survival. Difficult-to-treat or non-responsive patients should be treated with mycophenolate mofetil or, failing that, calcineurin inhibitors. Persistent failure to respond or lack of adherence to treatment result in end-stage liver disease. These patients, and those with fulminant liver failure (encephalopathy grade II-IV) at diagnosis, will require liver transplantation. The pathogenesis of AIH is not fully understood, although there is mounting evidence that genetic susceptibility, molecular mimicry and impaired immunoregulatory networks contribute to the initiation and perpetuation of the autoimmune attack. Liver damage is thought to be mediated primarily by CD4(pos) T-cells, although recent studies support the involvement of diverse populations, including Th17 cells. Animal models faithfully representing the human condition are needed to unravel the contribution of innate and adaptive, effector and regulatory immune responses. A deeper understanding of the pathogenesis of AIH is likely to contribute to the development of novel treatments, such as the adoptive transfer of autologous expanded antigen-specific regulatory T-cells, which ultimately aim to restore tolerance to liver-derived antigens., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

We have investigated the inflammatory infiltrate in post-transplant dn-AIH, a form of late insidious graft rejection, focusing on transcription factors defining effector and T-regs, using an antigen retrieval immunohistochemical method on archived liver tissue, and compared it with ACR and classical AIH. Paraffin-embedded liver biopsies from pediatric patients with dn-AIH (n = 10), ACR (n = 10), and AIH (n = 13) were selected randomly and stained using antibodies directed to CD4, CD8, T-bet (marker of Th1 polarization), GATA-3 (marker of Th2 polarization), FOXP3 (marker for T regulatory cells), IL-17, CD56 (NK cells), and perforin. Portal and lobular lymphocytic infiltrate was assessed semi-quantitatively. Prominent CD4, CD8, and T-bet positivity were present in both the lobular and portal infiltrate of all three conditions. Overall T-bet score of lobular inflammation in the dn-AIH group was lower than in the ACR and AIH groups (p = 0.02). In contrast, most samples showed absent or minimal GATA-3 positivity. FOXP3, CD56, IL-17, and perforin staining of mild to moderate severity were present in all three groups in both the portal and lobular infiltrate. A Th1 polarization of the inflammatory infiltrate characterizes dn-AIH, but also ACR and AIH., (© 2012 John Wiley & Sons A/S.)

The histological lesion of interface hepatitis, with its dense portal cell infiltrate consisting of lymphocytes, monocytes/macrophages and plasma cells, was the first to suggest an autoaggressive cellular immune attack in the pathogenesis of autoimmune hepatitis (AIH). Immunohistochemical studies, focused on the phenotype of inflammatory cells infiltrating the liver parenchyma, have shown a predominance of alphabeta-T cells. Amongst these cells, the majority have been CD4 helper/inducers, while a sizeable minority have consisted of CD8 cytotoxic/suppressors. Lymphocytes on non-T cell lineage included natural killer cells, monocytes/macrophages and B lymphocytes. For autoimmunity to arise, the self-antigenic peptide, embraced by an human leukocyte antigen (HLA) class II molecule, must be presented to an uncommitted T helper (T(H)0) lymphocyte by professional antigen-presenting cells. Once activated and according to the presence in the milieu of interleukin 12 (IL-12) or IL-4, T(H)0 lymphocytes can differentiate into T(H)1 cells, which are pivotal to macrophage activation; enhance HLA class I expression, rendering liver cells vulnerable to CD8 T-cell attack; and induce HLA class II expression on hepatocytes; or they can differentiate into T(H)2 cells, which produce IL-4, IL-10 and IL-13, cytokines favouring autoantibody production by B lymphocytes. Autoantigen recognition is tightly controlled by regulatory mechanisms, such as those exerted by CD4+CD25(high) regulatory T cells. Numerical and functional regulatory T cell impairment characterises AIH and permits the perpetuation of effector immune responses with ensuing persistent liver destruction. Advances in the study of autoreactive T cells stem mostly from AIH type 2, where the main autoantigen, cytochrome P450IID6 (CYP2D6), is known to enable characterisation of antigen-specific immune responses., (Copyright 2010 S. Karger AG, Basel.)

Auxiliary liver transplantation (ALT) permits the serial assessment of regeneration in livers of patients with acute liver failure (ALF). Forty-nine ALF patients [32 adults (median age, 23 years; range, 16-40 years) and 17 children (median age, 12 years; range, 1-15 years)] underwent ALT between 1994 and 2004 at King's College Hospital. Twenty-four patients had seronegative liver failure, 15 had acetaminophen toxicity, 4 had hepatitis B virus (HBV) infection, 3 had drug-induced liver failure, 2 had autoimmune hepatitis, and 1 had mushroom poisoning. Nine patients without post-ALT native liver histology were excluded from review. All acetaminophen-induced, HBV, and drug-related patients had diffuse injury. Twelve seronegative patients and the autoimmune hepatitis patient had a map-like injury. On follow-up, 9 acetaminophen-induced patients, 9 seronegative patients, 2 drug-induced ALF patients, 3 HBV patients, and the autoimmune patient recovered to a near-normal native liver with inconsequential scarring. The hepatocyte proliferative rate in diffuse necrosis was 27.4% (range, 3.1%-69.4%) at hepatectomy and sharply decreased after 8 days post-ALT, being minimal months and years after ALT. In conclusion, in patients undergoing ALT for ALF with a diffuse pattern of liver injury-mainly acetaminophen toxicity-hepatocyte proliferation occurs in the native liver within a few days of transplantation. If the injury is map-like (most cases of seronegative ALF), regeneration seems to involve variable hepatocellular proliferation and potential ductular hepatopoiesis, but sequential assessment is difficult because of sampling variation. The likelihood of histological recovery appears to be minimal in livers with total hepatocyte loss at the time of ALT., ((c) 2008 AASLD.)

Background: The quantitative loss of mitochondrial DNA (mtDNA) known as mtDNA depletion, often gives rise to liver disease. The diagnosis of mtDNA depletion syndrome is frequently imprecise, both for technical reasons and because of the lack of established age-adjusted normal ranges. We aimed to refine quantitative methods for diagnosing the hepatic type of mtDNA depletion syndrome, firstly by establishing an age-matched reference range for mitochondrial to nuclear DNA ratio (henceforth "mtDNA content") and secondly by investigating mtDNA in fibroblasts., Methods: By comparing realtime PCR with an established method for quantifying mtDNA content we established a reference range for young children using biopsy and post-mortem material from patients <15 years. In addition, we investigated the arrangement of mtDNA in nucleoids from fibroblasts using fluorescence microscopy., Results: Both methods showed that the mtDNA content of liver increases rapidly over the perinatal period. In a patient whose liver mtDNA content fell, but remained within the reference range, early investigation and age-matched controls were essential, as we found a progressive increase in muscle mtDNA copy number, respiratory chain activity and muscle power with age. In three further patients, fluorescence microscopy of the fibroblasts proved diagnostic. In one case a movement disorder was an important pointer., Conclusions: These cases highlight the (i) need for comparing mtDNA copy number data generated from patients to DNA isolated from an age-matched normal range from the tissue of interest and (ii) the utility of mtDNA staining with PicoGreen as a method to detect aberrant nucleoid morphology in mtDNA depletion patient fibroblast lines when affected tissues are not available for measuring mtDNA copy number.

Objectives: To describe hepatitis C virus (HCV)-related liver disease in a national cohort of patients who acquired their infections in childhood or adolescence and to assess risk factors for progressive disease and response to antiviral therapy., Patients and Methods: Demographic, laboratory, and clinical outcome data on 246 individuals who acquired HCV infection before the age of 16 years were extracted from the UK HCV National Register database. Logistic regression analysis was used to investigate the independent effects of sex, age, duration and route of infection, and comorbidity on histological stage of liver disease., Results: Median ages at enrollment and follow-up were 14.0 years (range, 2.2-29.6 years) and 19.2 years (range, 2.3-35.5 years), respectively. Mean duration of infection at enrollment was 8.5 years (standard deviation [SD], 3.3 years), and mean duration of follow-up was 4.5 years (SD, 4.5 years). Fifty-nine (24%) had persistently abnormal liver aminotransferase levels; 22% reported physical signs and symptoms of liver disease. Among 123 individuals with liver biopsies, 117 (95%) had abnormal histological findings. Ninety-eight individuals had biopsies referred for independent blind scoring; median Ishak grade and stage scores were 3 and 1, respectively. Presence of comorbidities (odds ratio [OR], 7.19; 95% CI, 2.00-26.17; P = 0.003) and female sex (OR, 0.31; 95% CI, 0.10-1.00; P = 0.05) were independently associated with histological stage scores greater than the median. A total of 110 individuals received antiviral therapy; 47% achieved a sustained response., Conclusions: HCV-related liver disease in those who acquired the infection in childhood or adolescence was mild for most, although comorbidity and female sex were associated with more advanced disease. Antiviral therapy in childhood or adolescence successfully eradicates the virus for many patients.

Background/purpose: Kasai portoenterostomy (KP) is regarded as first-line treatment for biliary atresia, although its postoperative course is often unpredictable. Hepatobiliary scintigraphy using technetium-labeled iminodiacetic acid derivatives offers a dynamic, objective assessment both of parenchymal liver function and restored biliary excretion. The value of postoperative radionuclide scans was assessed prospectively in a large population of post-KP infants., Methods: Radionuclide scans consisted of an intravenous dose of 20 MBq of 99mTc mebrofenin iminodiacetic acid and subsequent gamma camera imaging. Four scan variables were evaluated: the hepatic extraction fraction (HEF; ie, initial liver uptake divided by the peak vascular uptake), the half-life of tracer excretion (TEX), the shape of the excretion curve, and the presence of activity in the Roux loop at 4 hours postinjection. All infants had type 3 biliary atresia with a median age at KP of 59 days (24-120 days). To assess predictive value, outcome (clearance of jaundice and need for transplant) was assessed at 6 months (for 1-week scan) and 2 years (for 6-month scan)., Results: Eighty-seven infants underwent a radionuclide scan at 1 week post-KP. The median HEF was 34% (10%-90%). No relationship could be identified between HEF (P = .2) or excretion curve shape (P = .9) and outcome (at 6 months), and there were too few examples of a measurable TEX to allow meaningful comparison. The only predictive element at this time point was Roux loop activity (positive predictive value, 79%; negative predictive value, 53%; for "good" isotope bowel activity). Forty-four infants completed a second scan at 6 months. Median HEF increased from a baseline of 37% (11%-90%) to 64% (8%-100%) (P < .0001), although there was no significant intercorrelation (P = .12). The most predictive variables (of outcome at 2 years) were curve shape (positive predictive value, = 95%, negative predictive value, 82%) and TEX, and the least predictive was now Roux loop activity., Conclusions: Early (at 7 days) hepatic scintigraphy is not predictive of poor outcome in general, although Roux loop activity does indicate later success. Later hepatic scintigraphy (at 6 months) allows a detailed assessment of dynamic liver function with biliary excretion variables predictive of outcome in the medium term.

After several complications following percutaneous liver biopsy in patients with sickle cell disease, we reviewed our experience. We examined 14 patients with sickle cell disease who underwent a percutaneous liver biopsy. Clinicopathologic findings were correlated with outcome. Of 14 patients, 5 (36%) suffered serious hemorrhage; 4 died (80%; 28% of all patients). None of the 9 patients without biopsy complications was in an acute sickling crisis at the time of biopsy; 4 of 5 patients with complications were in acute sickling crisis. Of the 5 patients with complications, 4 underwent biopsy for an emergency indication. Chronic venous outflow obstruction, marked hepatic sequestration of erythrocytes, and sinusoidal dilatation were strongly associated with complications. Data obtained by biopsy in group 1 were not of substantial value in clinical management, in contrast to group 2 (8/9; 89%). Acute hepatic disease complicating sickle cell anemia represents a newly identified contraindication to percutaneous liver biopsy.

Background: Progressive destruction of intrahepatic bile ducts may determine outcome in extrahepatic biliary atresia (EHBA) despite successful portoenterostomy. The aim of this study was to characterize the inflammatory infiltrate of a large series of cases of biliary atresia and relate these findings to clinical outcome., Methods: Immunohistochemical analysis was performed on frozen tissue sections of extrahepatic biliary tree and liver biopsies obtained (August 1996 to March 1998) from 28 infants with EHBA and 8 liver biopsy specimens from age-matched controls with other cholestatic liver disorders. A semiquantitative scoring system was designed to evaluate the staining with a panel of antibodies to the CD4, CD8, CD25, CD56, CD68, CD71 antigens and to HLA-DR, ICAM-1, VCAM-1, E-selectin and LFA-1. The infants then underwent followup prospectively and divided into 2 prognostic groups at 12 months postoperatively: those who had cleared their jaundice (graded as a good outcome [n = 19]), and those who required liver transplantation or who had failed to clear their jaundice (defined as > 50 micromol/L; graded as poor outcome [n = 9])., Results: CD4(+) lymphocytes and CD56(+) (NK cells) predominated in the liver of infants with EHBA as compared with controls. The infiltrating cells exhibited marked proliferation (CD71 expression) and activation (particularly LFA-1 but also CD25 expression). A smaller subpopulation of the cells also expressed VCAM and E-selectin. HLA-DR was strongly expressed on Kupffer cells and to a lesser extent on proliferating bile ducts and sinusoidal endothelium. Expression of the majority of markers was lower in the remnant bile duct tissue than in the liver of EHBA (P <.05) with only HLA-DR and LFA-1 (on infiltrating cells) and ICAM (on endothelium) expressed strongly in the remnant bile duct tissue. Although quantitatively less pronounced, all of these immunohistochemical features also were noted in non-EHBA cholestatic liver tissue. A good outcome at 12 months was associated with lower CD68 (macrophage) expression in both the liver (P <.05) and biliary tree (P <.05) and with reduced expression of ICAM-1 (P =.05) on infiltrating cells in the biliary remnant., Conclusions: Immunohistochemical patterns of immune-mediated liver injury and inflammation were prevalent features at the time of portoenterostomy. They were neither exclusive to nor characteristic of EHBA. A reduction in the expression of the macrophage marker (CD68) within the liver and biliary remnants and reduction of ICAM-1 expression on infiltrating cells in the biliary remnants appear to be associated with a better postoperative prognosis., (Copyright 2001 by W.B. Saunders Company.)

The immune system's ability to distinguish self from nonself is essential for both host defence against microbial antigens and protection of self-antigens from autoimmune destruction. Such discrimination is complicated by extensive structural homology shared between micro-organisms and self-antigens, a condition known as molecular mimicry. Molecular mimicry provides the foundation for an immune response directed against an exogenous agent such as a virus to cross-react with mimicked host self sequences, leading to autoimmunity, and in some cases, tissue injury and autoimmune disease. In this review we analyse studies investigating the role of molecular mimicry and cross-reactive immunity in liver-related autoimmunity.

The mechanism of liver giant cell formation is not clarified. Some authors consider the giant cells regenerative, others, degenerative. Paraffin sections of 10 archival cases of idiopathic neonatal hepatitis (INH), 8 of extrahepatic biliary atresia (EHBA), and 5 normal liver samples were immunostained with two well-characterized cell proliferation markers: anti-PCNA monoclonal antibody (MAb) (clone PC-10) and MAb MIB-1, which detects Ki-67, a nuclear proliferation-related antigen. In addition, polyclonal antibody to carcinoembryonic antigen (CEA) was used to identify remnants of canalicular, therefore hepatocytic, membranes in giant cells. Quantitative analysis of immunostaining was done by estimating PCNA and Ki-67 indices separately in giant cells and in nongiant hepatocytes. In normal samples, mean PCNA and Ki-67 indices were 1. 22% and 0.74%, respectively. In the cases of INH and EHBA, only a small minority of giant cells showed PCNA or Ki-67 staining limited to occasional peripherally located nuclei. PCNA and Ki-67 indices were significantly higher in the non-giant cell compartment. CEA staining was seen only in rare giant cells as centrally located canalicular remnants bordered by polarized nuclei, suggesting that they had been formed from rosettes through dissolution of cell membranes. Other giant cells shared CEA-labeled canalicular membranes with mononuclear hepatocytes in rosettes. These findings indicate that the giant cells in INH and EHBA are not regenerative cells, they are not formed by amitotic division of nuclei in syncytia, and that fusion of rosette-forming hepatocytes is a possible mechanism of their formation.

The liver biopsies of patients with autoimmune liver diseases have a dense portal tract mononuclear cell infiltrate. To investigate whether these cells produce tumour necrosis factor-alpha and interferon-gamma, cytokines which could be involved in the autoimmune attack through a direct cytopathic effect and/or through induction/enhancement of major histocompatibility complex antigen expression, we immunohistochemically stained cryostat liver sections from 21 children with autoimmune liver disease and from 15 children with metabolic liver disorders and histological evidence of portal tract inflammation as controls. Tumour necrosis factor-alpha and interferon-gamma producing cells were detected simultaneously within the inflammatory cell infiltrate in the liver biopsies of 18 patients with autoimmune liver disease, but only one patient with a metabolic disorder was positive for tumour necrosis factor-alpha. There was a significant correlation between frequency of tumour necrosis factor-alpha and interferon-gamma producing cells, intensity of inflammatory cell infiltrate (p < 0.03 and p < 0.05, respectively) and transaminase levels (p < 0.008 and p < 0.03, respectively). These results suggest that tumour necrosis factor-alpha and interferon-gamma play a pathogenic role in autoimmune liver cell damage.

Three patients with stable liver function after Kasai portoenterostomy developed acute liver failure secondary to liver necrosis. Doppler ultrasound at presentation revealed reversed diastolic hepatic arterial blood flow. Two patients survived after urgent liver transplantation. Liver necrosis should be suspected in children with chronic liver disease presenting with fever and rapidly deteriorating liver function.

Methodological differences in major histocompatibility complex (MHC) antigen detection were investigated on isolated, viable hepatocytes and cryostat hepatic sections from 27 children with liver disorders, six of whom had normal histology. Class I antigens were constantly found on sections using a three step immunoperoxidase technique after acetone/chloroform fixation, other techniques being less sensitive, or on isolated hepatocytes by indirect immunofluorescence alone. With mechanical isolation the percentage of positivity ranged from 85 to 100%, while with collagenase isolation it ranged from 22 to 49% on immediate testing, and from 53 to 80% after 24 hour incubation. Class II antigens were only detected in one patient with autoimmune chronic active hepatitis and two with primary sclerosing cholangitis. Flow cytofluorimetric analysis in 11 cases confirmed class II or class I positivity, or both, on isolated hepatocytes, allowing MHC antigen expression on hepatocytes to be measured. Class I and II antigen detection on hepatocytes is influenced by the technique used. Although class I antigens are invariably expressed on hepatocytes, class II antigens are only found on hepatocytes from patients with immune mediated liver disorders.

Controversy exists regarding major histocompatibility complex antigen expression on hepatocytes. In this study, hepatocyte expression of class I and II major histocompatibility complex antigens was investigated in diseased and normal livers, using indirect immunofluorescent staining of mechanically isolated, viable hepatocytes. Hepatocytes were obtained from 76 children: 10 with autoimmune chronic active hepatitis, nine with primary sclerosing cholangitis, nine with chronic hepatitis B virus infection, five after liver transplantation, 19 with extrahepatic biliary atresia, 11 with alpha 1-antitrypsin deficiency, four with idiopathic neonatal hepatitis and nine with histologically normal liver. Immunohistochemistry was performed in all cases; flow cytofluorimetry was performed for class I antigens in 38 cases and performed for class II antigens in 18 cases. From three children with autoimmune chronic active hepatitis and two with chronic hepatitis B virus infection, isolated hepatocytes were also incubated with gamma-interferon before staining and analysis. By fluorescence microscopy, class I antigens were detected on hepatocytes from all children, the highest percentage (100%) of positive cells and the most intense staining were observed in untreated patients with autoimmune chronic active hepatitis or primary sclerosing cholangitis and in those with acute rejection of a liver transplant. Reduced class I antigen expression occurred in chronic hepatitis B virus infection. Class II antigens were only detected on hepatocytes from eight patients: three with autoimmune chronic active hepatitis and five with primary sclerosing cholangitis, all untreated. Flow cytofluorimetric analysis confirmed the results obtained by fluorescence microscopy, but it also demonstrated a weak class II antigen expression during liver allograft rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate mechanisms of hepatocyte injury, lymphocytes from 41 children with chronic liver disease were incubated with autologous liver cells in a microcytotoxicity assay. Cytotoxicity was significantly increased in 18 of 25 patients with chronic hepatitis B virus (HBV) infection, in five of nine with "autoimmune" chronic active hepatitis (CAH), and in only one of seven with histologically inactive liver disorders. There was a good correlation between cytotoxicity and biochemical and histologic markers of disease activity in children with autoimmune CAH, whereas in HBsAg-positive disease a positive correlation was found only with serum alanine aminotransferase (SGPT). Children with autoimmune CAH receiving steroid treatment had normal cytotoxicity, whereas increased values were found in two of three HBsAg-positive patients receiving prednisolone. Fractionation studies revealed that non-T cells were cytotoxic in both autoimmune and HBcAg-positive chronic liver disease. T cell cytotoxicity was exclusively found in children with chronic HBV infection, particularly with HBc antigenemia. Blocking experiments showed that T-lymphocytes from HBsAg-positive children reacted with HBV core antigen on the hepatocyte surface. Non-T cells were directed against hepatocyte membrane antigens in both HBsAg-positive and HbsAg-negative children. These results suggest that different immune mechanisms of liver damage are involved in autoimmune and HBsAg-positive chronic liver disease.

An indirect immunofluorescence technique was used to investigate the immunoglobulin class, IgG subclass, light chain type and complement fixing ability of anti-liver kidney microsomal antibody (anti-LKM) in the sera of six children and five adults with autoimmune chronic active hepatitis (aCAH). Anti-LKM titres ranged from 1/80 to 1/20,480. In the children, the antibody belonged to the IgG1 subclass alone (titre 1/80-1/20,480) and was able to fix complement (titre 1/40-1/5120). In the adult group, antibody belonged to the IgG1 subclass in three cases (titre 1/40-1/640) whilst two belonged to both IgG1 (titre 1/640) and IgG4 (titre 1/40, 1/640). Such subclass restriction is similar to that found in other autoimmune disorders and may be genetically determined. Investigation of the light chain constituent of anti-LKM revealed that the kappa to lambda ratio was consistent with a polyclonal antibody response. To investigate the nature of the antigen to which anti-LKM is directed, the ability of these sera to bind to the surface membrane of isolated human hepatoma cells (Alexander cells) was investigated. Four of the eleven sera showed significant binding activity. Prior incubation of these four sera with Alexander cells abolished their membrane binding activity, but did not alter the anti-LKM titre. These results suggest that anti-LKM binds to cytoplasmic constituents alone and does not cross-react with surface antigens.

Previous investigations have shown that patients with fulminant hepatic failure after halothane anaesthesia have a circulating antibody which reacts with an antigen present on the surface of halothane-altered hepatocytes. In the present study, it has been shown that the expression of the antigen is associated with the oxidative metabolism of halothane, in contrast with results of other groups which have shown that the reductive route is involved in the direct hepatotoxic reaction attributed to halothane.

To investigate the possible role of cell mediated cytotoxicity in the pathogenesis or perpetuation of liver damage associated with alpha 1-antitrypsin (AAT) deficiency, peripheral blood lymphocytes (PBL) from 13 children with PiZZ phenotype who had had liver disease in infancy were incubated with autologous hepatocytes in a microcytotoxicity assay. There was a clear trend for cytotoxicity to increase with age and thus significantly increased cytotoxicity was found in four cases older than 2 years, while intermediate values were recorded in three children between 6 months and 2 years and normal values in children younger than 6 months. Fractionation of PBL into T and non-T-enriched subsets showed that both were involved in the cytotoxic reaction. A purified liver membrane lipoprotein preparation (LSP) inhibited both T and non-T-cell cytotoxicity suggesting that LSP is a major target antigen in this system. Control experiments performed in infants with neonatal hepatitis syndrome, but with normal Pi phenotype, showed consistently increased cytotoxicity values. Cell-mediated immune reactions directed against autologous hepatocytes develop late in the course of the liver disease associated with AAT deficiency. While this reaction cannot be involved in the pathogenesis of the initial liver lesion, it may contribute to perpetuation of liver damage.

The lack of information on the state of fetal liver in PiZZ alpha-1-antitrypsin (AAT) deficiency and a single case report claiming a hypoplasia of interlobular bile ducts in a 20-week PiZZ fetus, instigated this histologic study of the liver in five PiZZ fetuses, 17-20 weeks of gestation and five age-matched controls. We found no difference between the percentage of portal tracts with identifiable bile ducts in the PiZZ (median 22.2%, range 21%-23%) and in the control (median 21.4%, range 20%-24%) on hematoxylin- and eosin-stained sections. Immunostaining with AE1, a monoclonal antibody to cytokeratins restricted to normal bile ducts, doubled the number of recognizable ducts in both PiZZ and control livers. In four PiZZ livers, but in none of the controls, granular deposits of AAT could be detected by specific immunoperoxidase staining. We conclude that an apparent paucity of interlobular bile ducts is normal in the 20-week fetal liver, and our data may be taken as reference for future study dealing with similar material. Except for the cytoplasmic deposition of granules immunoreactive to AAT antiserum, there was no evidence of any developmental anomaly, in particular of the bile duct system in these five PiZZ fetal livers.

Biliary obstruction by viscid mucus, although important, may not be the only factor for the development of liver disease in some patients with cystic fibrosis. In the present study the relationship between immune responses to liver antigens and the presence of liver damage was investigated using the leucocyte migration test and lymphocyte cytotoxicity to isolated rabbit hepatocytes. Inhibition of leucocyte migration by purified liver-specific lipoprotein, derived from hepatocyte plasma membrane, was found in 9 of 11 children with liver disease, but in only 5 of 14 with cystic fibrosis and no overt liver disease (P < 0.025). Lymphocyte toxicity to isolated rabbit hepatocytes was significantly increased in 10 of 13 children with liver disease, but in only 6 of 29 children without liver disease (P < 0.001). Experiments using lymphocyte subpopulations showed that the cytotoxicity was mediated by a non-T-cell population and could be blocked with liver-specific lipoprotein in 7 out of 10 cases, suggesting that the reaction in these patients was specifically directed against liver-specific lipoprotein. The study suggests that sensitisation against liver membrane antigens, whether arising primarily or secondarily in some way to other hepatic lesions, may contribute to the progression of liver damage in cystic fibrosis.

Circulating antibodies reacting specifically with the cell membrane of hepatocytes isolated from halothane-anesthetized rabbits were detected in nine of 11 patients with fulminant hepatic failure after helothane-induced anesthesia. The immunoglobulin deposition, as revealed by immunofluorescence, showed a granular pattern on the hepatocyte surface membrane. Preincubation of halothane-pretreated, but not of control, hepatocytes with serum containing this antibody rendered them susceptible to cytotoxic effects of normal lymphocytes in vitro. Control studies using serum from subjects repeatedly exposed to halothane without the development of liver damage, and from patients with viral and toxic liver injury have confirmed the specificity of these findings to serve halothane-associated liver injury. These results provide further evidence of an immunologic component in this condition.

A radioimmunometric technique for the detection of autoantibodies to liver membrane antigens has been developed using Alexander cells, a human hepatocellular carcinoma cell line. After incubation of Alexander cells with serum, antimembrane antibodies were detected by addition of 125I-labeled Protein A. Binding ratios in 15 children with uncontrolled autoimmune chronic active hepatitis and in seven children with primary sclerosing cholangitis were significantly higher than in 18 age-matched normal controls. Nine patients with inactive autoimmune chronic active hepatitis, 13 with alpha 1-antitrypsin deficiency and five with fulminant hepatic failure had ratios similar to controls. In nine patients with Wilson's disease, there was a modest but significant increase in binding ratio. In four children with autoimmune chronic active hepatitis, binding ratios fell during effective immunosuppressive therapy. Sera from patients with systemic lupus erythematosus or rheumatoid arthritis gave normal results, excluding that binding derives from Fc-mediated immune complex capture. A positive correlation was found between Alexander cell binding values and anti-liver-specific protein antibody titers, suggesting that the two assays detect antibodies against shared antigenic determinants. The Alexander cell assay is a simple, rapid and sensitive technique to detect antibody to liver cell membrane antigens.

Lymphocytes from three of four patients with severe unexplained hepatitis following halothane anaesthesia were cytotoxic in vitro for liver cells isolated from rabbits following halothane anaesthesia, and less so for control hepatocytes. While the latter reaction could be blocked by addition of a purified liver membrane lipoprotein (LSP), this had no effect on the cytotoxicity to "halothane" hepatocytes. These results provide evidence that patients with severe halothane-associated hepatitis are sensitised to a liver cell antigen distinct from LSP, which arises as a result of halothane anaesthesia.

A high percentage of patients with acute leukaemia in established remission develop chronic liver disease: how important hepatitis-B-virus (HBV) infection is as an aetiological factor is not clear. The presence of HBV markers in liver and serum of 23 leukaemic children with liver disease was investigated at the time of a diagnostic biopsy just before treatment withdrawal. Although, at this time, none had HBV antigens or antibodies in the serum by radioimmunoassay, HBsAg was detected by direct immunofluorescence in the cytoplasm of hepatocytes in 13 children, 7 of whom also had hepatitis-B core or e antigens in hepatocyte nuclei. This pattern of both cytoplasmic and nuclear fluorescence was present in 4 of 6 patients with the histological features of chronic active hepatitis on liver biopsy. The failure of release of viral antigens into serum and the absence of an adequate immune response were probably due to the intense chemotherapy used to induce and maintain remission, since HBV markers appeared in the serum within 15 months of stopping treatment in 8 of the children in whom viral antigens had been detected in liver tissue but in none of those whose biopsy specimens were negative by immunofluorescence. These results suggest that HBV infection may be an important cause of chronic liver disease in children with leukaemia and show that during treatment serological tests may fail to detect the presence of the virus.

Hepatocytes isolated from patients with chronic liver disease are often covered by immunoglobulin. The aim of the present study was to establish whether this surface immunoglobulin (SIg) mediates liver cell damage. Freshly isolated hepatocytes from percutaneous liver biopsy of 16 patients with chronic active hepatitis (CAH) (6 HBsAg positive), 3 with HBsAg-positive chronic lobular hepatitis (CLH), 5 with HBsAg-positive chronic persistent hepatitis (CPH) and 12 with minor histological abnormalities (MHA) (5 HBsAg positive) were divided into two aliquots. One was studied for the presence of membrane-bound immunoglobulin and the third component of complement by direct immunofluorescence and the other was incubated, in an allogeneic cytotoxic assay, with peripheral blood mononuclear cells prepared from healthy volunteers as a source of effectors for antibody-dependent cell-mediated cytotoxicity (ADCC). Liver biopsies were scored for portal and parenchymal inflammatory activity. The percentage of SIg positive hepatocytes was significantly higher in patients with CAH (median 52.5%) than in patients with CLH/CPH (20.5%) or in patients with MHA (1%). Percentages of SIg-positive liver cells were significantly correlated with total liver biopsy scores and with both portal or parenchymal scores considered independently. SIg were found to belong to the IgG class in all groups of patients. When hepatocytes were cultured with normal human lymphocytes, allogeneic cytotoxicity values were significantly higher in patients with CAH (median 34%) than in patients with CLH and CPH (18%) or in those with MHA (12%). Percentage cytotoxicity was positively correlated with total biopsy scores and with portal activity but not with parenchymal activity, suggesting that ADCC might play a damaging role mainly in the portal areas.(ABSTRACT TRUNCATED AT 250 WORDS)