Antibodies to soluble liver antigen/liver pancreas and HLA risk factors for type 1 autoimmune hepatitis

Advances in the current treatment of autoimmune hepatitis

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

Autoantibody-negative autoimmune hepatitis

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

Anti-α actinin antibodies as new predictors of response to treatment in autoimmune hepatitis type 1

BACKGROUND

We reported that combined presence of autoantibodies (Abs) against filamentous-actin (AFA) and α-actinin are specific for autoimmune hepatitis type 1 (AIH-1) diagnosis.

AIM

To explore our data and assess whether anti-α-actinin and AFA Abs could be used as indicators of response to treatment and predictors of AIH-1 flares in a large cohort of AIH-1 patients.

METHODS

Seven hundred and sixty-four serial serum samples of 86 consecutive AIH-1 patients, 509 pathological and 110 normal controls were tested for the presence of anti-α-actinin and AFA Abs by an in-house IgG-specific ELISA and a standardised commercially available ELISA respectively. Patients sera were divided into baseline group (active disease before treatment initiation, n = 86) and then according to treatment response into group A-responders (n = 40 patients), group B-relapsers/incomplete responders (n = 37 patients) and group C-not-treated (n = 9 patients).

RESULTS

Anti-α-actinin and AFA levels were significantly higher at baseline. Double reactivity against α-actinin and AFA was associated with disease activity (OR 4.9; 95% CI: 2.7-9). Anti-α-actinin optical densities (ODs) before treatment decreased significantly at first remission (P < 0.05). Treatment response was associated with anti-α-actinin Abs negativity before treatment (OR 3.4; 95% CI: 1.3-8.9) and absence of double positivity for anti-α-actinin and AFA Abs before treatment (OR 3.8; 95% CI: 1.4-10.4). Responders had lower baseline levels of anti-α-actinin than relapsers and/or incomplete responders (P = 0.002). Binary logistic regression revealed lower levels of anti-α-actinin as the only independent predictors of response (P = 0.05).

CONCLUSIONS

Anti-α-actinin Abs at baseline appear to predict treatment response and therefore they might be used for monitoring treatment outcome in AIH-1.

Prognostic implications of antibodies to Ro/SSA and soluble liver antigen in type 1 autoimmune hepatitis

BACKGROUND

Antibodies to soluble liver antigen are frequently co-expressed with antibodies to ribonucleoprotein/Sjögren's syndrome A (Ro/SSA) in autoimmune hepatitis.

AIMS

Our goals were to evaluate the prognostic implications of antibodies to Ro/SSA in type 1 autoimmune hepatitis and to determine their independence from antibodies to soluble liver antigen.

METHODS

Three hundred and seventy-six serum samples from 170 patients were tested by enzyme immunoassays.

RESULTS

Sixty-five patients (38%) had antibodies to Ro52; 11 patients (6%) had antibodies to Ro60; and 27 patients had antibodies to soluble liver antigen (16%). Twenty-six patients with antibodies to Ro52 had antibodies to soluble liver antigen (40%), and 26 patients with antibodies to soluble liver antigen had antibodies to Ro52 (96%). Patients with antibodies to Ro52 and antibodies to soluble liver antigen had a higher frequency of human leucocyte antigen (HLA) DRB1(*) 03 (78 vs 50%, P=0.05) and lower occurrence of HLA DRB1(*) 04 (22 vs 57%, P=0.01) than patients with antibodies to Ro52 alone. Antibodies to Ro52 alone [hazard ratio (HR), 2.90; 95% confidence interval (CI), 1.18-7.14, P=0.02] and antibodies to Ro52 in conjunction with antibodies to soluble liver antigen (HR, 2.98; 95% CI, 1.07-8.43, P=0.04) were independently associated with the development of cirrhosis and hepatic death or liver transplantation.

CONCLUSIONS

Antibodies to Ro52 alone and antibodies to Ro52 in conjunction with antibodies to soluble liver antigen are independently associated with a poor prognosis in type 1 autoimmune hepatitis. The prognostic implications ascribed to antibodies to soluble liver antigen may reflect their almost invariable concurrence with antibodies to Ro52.

Cryptogenic chronic hepatitis and its changing guise in adults

Cryptogenic chronic hepatitis is a disease that is unexplained by conventional clinical, laboratory and histological findings, and it can progress to cirrhosis, develop hepatocellular carcinoma, and require liver transplantation. The goals of this review are to describe the changing phenotype of cryptogenic chronic hepatitis in adults, develop a diagnostic algorithm appropriate to current practice, and suggest treatment options. The frequency of cryptogenic hepatitis is estimated at 5.4%. Cryptogenic cirrhosis is diagnosed in 5-30% of patients with cirrhosis, and it is present in 3-14% of adults awaiting liver transplantation. Nonalcoholic fatty liver disease has been implicated in 21-63% of patients, and autoimmune hepatitis is a likely diagnosis in 10-54% of individuals. Viral infections, hereditary liver diseases, celiac disease, and unsuspected alcohol or drug-induced liver injury are recognized infrequently in the current cryptogenic population. Manifestations of the metabolic syndrome heighten the suspicion of nonalcoholic fatty liver disease, and the absence of hepatic steatosis does not discount this possibility. The diagnostic scoring system of the International Autoimmune Hepatitis Group can support the diagnosis of autoimmune hepatitis in some patients. Certain genetic mutations may have disease-specificity, and they suggest that some patients may have an independent and uncharacterized disease. Corticosteroid therapy is effective in patients with autoimmune features, and life-style changes and specific therapies for manifestations of the metabolic syndrome are appropriate for all obese patients. The 1- and 5-year survivals after liver transplantation have ranged from 72-85% to 58-73%, respectively.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is an inflammatory liver disease that mainly affects females. It is characterized histologically by interface hepatitis, biochemically by increased aspartate and alanine aminotransferase levels, and serologically by the presence of autoantibodies and increased levels of immunoglobulin G. AIH affects both adults and children, and is particularly aggressive in the latter group. It is a relatively rare but devastating disease, which progresses rapidly unless immunosuppressive treatment is started promptly. With appropriate treatment 80% of patients achieve remission and long-term survival. Those patients who progress to end-stage liver disease because they are unresponsive or nonadherent to treatment, and those with fulminant liver failure (encephalopathy grade II-IV) at diagnosis, require liver transplantation. Seropositivity for smooth muscle and/or antinuclear antibodies defines type 1 AIH, while positivity for liver kidney microsomal type 1 antibodies defines type 2 AIH. The primary cause of AIH is unknown; however, considerable knowledge about the mechanisms of liver damage involved has been gathered over the past 30 years, which is likely to provide the basis for specific modes of treatment and a possible cure.

Autoimmune hepatitis: a review of current diagnosis and treatment

Autoimmune hepatitis (AIH) is a chronic inflammatory disorder characterized by periportal inflammation, elevated immunoglobulins, autoantibodies, and a dramatic response to immunosuppression. An environmental agent is hypothesized to trigger an immune-mediated attack directed against liver antigens in genetically predisposed individuals. A plethora of clinical presentations can be seen ranging from chronic indolent disease to fulminant hepatic failure, and diagnosis requires exclusion of other causes of liver disease. Corticosteroid therapy must be instituted early and modified in an individualized fashion. Treatment decisions are often complicated by the diverse clinical manifestations, uncertainty about natural history, evolving ideas about treatment end points, and a multitude of alternative immunosuppressive agents. Achieving normal liver tests and tissue is the ideal treatment end point, but needs to be weighed against the risk of side effects. Decompensated patients may benefit from early liver transplantation. Long-term prognosis is excellent with early and aggressive initiation of therapy. Our paper discusses AIH, giving a detailed overview of its clinical presentation, risk factors, immunopathogenesis, up-to-date diagnostic criteria, current updates in therapy with a brief discussion of AIH in pregnancy, and long-term implications for cirrhosis and hepatocellular carcinoma in AIH patients.

Optimizing management in autoimmune hepatitis with liver failure at initial presentation

Autoimmune hepatitis (AIH) is a disease of unknown etiology, its hallmark being ongoing hepatic inflammation. By its very nature, it is a chronic condition, although increasingly, we are becoming aware of patients with acute presentations, some of whom may have liver failure. There are very limited published data on patients with AIH with liver failure at initial diagnosis, which consist mostly of small retrospective studies. As a consequence, the clinical features and optimal management of this cohort remain poorly defined. A subset of patients with AIH who present with liver failure do respond to corticosteroids, but for the vast majority, an urgent liver transplantation may offer the only hope of long-term survival. At present, there is uncertainty on how best to stratify such a cohort into responders and non- responders to corticosteroids as soon as possible after hospitalization, thus optimizing their management. This editorial attempts to answer some of the unresolved issues relating to management of patients with AIH with liver failure at initial presentation. However, it must be emphasized that, at present, this editorial is based mostly on small retrospective studies, and it is an understatement that multicenter prospective studies are urgently needed to address this important clinical issue.

Alpha-actinin: a multidisciplinary protein with important role in B-cell driven autoimmunity

Alpha-actinin (α-actinin) is a ubiquitous cytoskeletal protein, which belongs to the superfamily of filamentous actin (F-actin) crosslinking proteins. It is present in multiple subcellular regions of both muscle and non-muscle cells, including cell-cell and cell-matrix contact sites, cellular protrusions and stress fiber dense regions and thus, it seems to bear multiple important roles in the cell by linking the cytoskeleton to many different transmembrane proteins in a variety of junctions. Four isoforms of human α-actinin have already been identified namely, the "muscles" α-actinin-2 and α-actinin-3 and the "non-muscles" α-actinin-1 and α-actinin-4. The precise functions of α-actinin isoforms as well as the precise role and significance of their binding to F-actin particularly in-vivo, have been elusive. They are generally believed to represent key structural components of large-scale F-actin cohesion in cells required for cell shape and motility. α-Actinin-2 has been implicated in myopathies such as nemalin body myopathy, hypertrophic and dilated cardiomyopathy and it may have at least an indirect pathogenetic role in diseases of the central nervous system (CNS) like schizophrenia, epilepsy, ischemic brain damage, CNS lupus and neurodegenerative disorders. The role of "non-muscle" α-actinins in the kidney seems to be crucial as an essential component of the glomerular filtration barrier. Therefore, they have been implicated in the pathogenesis of familial focal segmental glomerulosclerosis, nephrotic syndrome, IgA nephropathy, focal segmental glomerulosclerosis and minimal change disease. α-Actinin is also expressed on the membrane and cytosol of parenchymal and ductal cells of the liver and it seems that it interacts with hepatitis C virus in an essential way for the replication of the virus. Finally α-actinin, especially α-actinin-4, has been implicated in cancer cell progression and metastasis, as well as the migration of several cell types participating in the immune response. Based on these functions, the accumulating reported evidence of the importance of α-actinin as a target autoantigen in the pathogenesis of autoimmune diseases, particularly systemic lupus erythematosus and autoimmune hepatitis, is also discussed along with the possible perspectives that are potentially emerging from the study of this peculiar molecule in health and disease.

Autoantibodies as prognostic markers in autoimmune liver disease

Certain autoantibodies in autoimmune liver disease have prognostic implications that are under-utilized and under-developed. The goals of this review are to indicate progress in characterizing the autoantibodies with prognostic connotations and to indicate the feasibility and importance of discovering other markers. Prime source and review articles in English were selected by a Medline search through 2010. Antibodies to soluble liver antigen, actin, liver cytosol type 1, asialoglycoprotein receptor, chromatin, cyclic citrullinated peptide, and uridine glucuronosyltransferases have been associated with the occurrence, severity, and progression of autoimmune hepatitis, and antibodies to Sp100, gp210, and centromere have had similar implications in primary biliary cirrhosis. Antibodies to soluble liver antigen have shown the most promise in autoimmune hepatitis as they have been associated with severe histological changes, long durations of treatment, relapse after drug withdrawal, and high frequency of liver failure. Antibodies to the nuclear rim pore protein, gp210, have shown the most promise in primary biliary cirrhosis as they have been associated with severe interface hepatitis, lobular inflammation, and progression to liver failure. The major limitations of the autoantibodies have been their lack of standardized assays, low negative predictabilities, and fluctuating levels. Performance parameters will improve as critical pathogenic pathways, comprehensive testing batteries, and standardized assays through international exchange workshops are developed. Progress has been made in identifying the serological markers of prognosis in autoimmune liver disease, and they promise to reflect critical disease mechanisms and enhance patient management.

Advances in the diagnosis, pathogenesis, and management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterized by chronic inflammation of the liver, interface hepatitis (based on histologic examination), hypergammaglobulinemia, and production of autoantibodies. Many clinical and basic science studies have provided important insights into the pathogenesis and treatment of AIH. Transgenic mice that express human antigens and develop autoantibodies, liver-infiltrating CD4(+) T cells, liver inflammation, and fibrosis have been developed as models of AIH. AIH has been associated with autoantibodies against members of the cytochrome P450 superfamily of enzymes, transfer RNA selenocysteine synthase, formiminotransferase cyclodeaminase, and the uridine diphosphate glucuronosyltransferases, whereas alleles such as DRB1*0301 and DRB1*0401 are genetic risk factors in white North American and northern European populations. Deficiencies in the number and function of CD4(+)CD25(+) (regulatory) T cells disrupt immune homeostasis and might be corrected as a therapeutic strategy. Treatment can be improved by continuing corticosteroid therapy until normal liver test results and normal liver tissue are within normal limits, instituting ancillary therapies to prevent drug-related side effects, identifying problematic patients early, and providing long-term maintenance therapy after patients experience a first relapse. Calcineurin inhibitors and mycophenolate mofetil are potential salvage therapies, and reagents such as recombinant interleukin-10, abatacept, and CD3-specific antibodies are feasible as therapeutics. Liver transplantation is an effective salvage therapy, even in the elderly, and AIH must be considered in all patients with graft dysfunction after liver transplantation. Identification of the key defects in immune homeostasis and antigen targets will direct new therapies.

The role of autoantibodies as diagnostic markers of autoimmune hepatitis

Autoantibody testing is the first step towards the diagnosis of autoimmune hepatitis, and it is essential in the evaluation of acute and chronic hepatitis of undetermined cause and allograft dysfunction following liver transplantation. A standard diagnostic repertoire has been promulgated, and other autoantibodies are emerging that may have prognostic value. Supplemental autoantibodies may prove useful in assessing patients who lack the standard markers or who are distinctive among those with conventional markers. Serologic testing will improve as assays are standardized by serum exchange workshops, core diagnostic batteries are codified and promulgated, and markers emerge that are tightly associated with pathogenic mechanisms, and closely reflect disease activity and outcome.

Anti-Soluble Liver Antigen (SLA) Antibodies in Chronic HCV Infection

Hepatitis C infection is associated with autoimmune disorders, such as the production of autoantibodies. Anti-LKM1 and anti-LC1, immunomarkers of type 2 autoimmune hepatitis, have been previously associated with a HCV infection. Anti-Soluble-Liver-Antigen autoantibodies (SLA) are specifically associated with type 1 and type 2 autoimmune hepatitis and more closely related to patients who relapse after steroid therapy. The recent molecular cloning of the soluble liver antigen provides the opportunity to develop more specific tests for the detection of antibodies against it. The aim of this work is to characterize anti-soluble-liver autoantibodies in sera from patients chronically infected by HCV. A recombinant cDNA from activated Jurkat cells coding for the full length tRNP(Ser)Sec/SLA antigen was obtained. ELISA, Western Blot and immunoprecipitation tests were developed and used to search for linear and conformational epitopes recognized by anti-SLA antibodies in sera from patients chronically infected by HCV. Anti-soluble liver antigen antibodies were found in sera from 10.4% of HCV-infected patients. The prevalence was significantly increased to 27% when anti-LKM1 was also present. Most anti-SLA reactivity was directed against conformational epitopes on the antigen. The means titers by ELISA were lower than those obtained in type 2 AIH. The result of autoantibody isotyping showed a subclass restriction to IgG1 and also IgG4. This study shows the presence of anti-SLA antibodies in approximately 10% of HCV infected patients. The prevalence of SLA autoantibodies in HCV infected patients increases when LKM1 autoantibodies are also present. The relationship between the prevalence of this characteristic autoimmune hepatitis autoantibody and the implication of an autoimmune phenomenon in the liver injury of patients chronically infected by HCV needs further investigation.

Nonstandard Antibodies as Prognostic Markers in Autoimmune Hepatitis

BACKGROUND

Antibodies to actin, chromatin, soluble liver antigen/liver pancreas and liver cytosol type 1 have been ascribed prognostic value in autoimmune hepatitis.

AIM

Evaluate the performance parameters of these nonstandard autoantibodies and determine the critical battery for clinical application.

METHODS

All antibodies were tested concurrently by enzyme immunoassay in 106 patients who had reached a treatment outcome. Tests were repeated in 149 serum samples obtained later to assess durability of the findings.

RESULTS

Antibodies to chromatin and soluble liver antigen/liver pancreas were superior to the other markers in predicting relapse. Patients with antibodies to chromatin and/or soluble liver antigen/liver pancreas relapsed more frequently than patients without these markers (100 versus 79%, p < 0.0003). Maximum sensitivity and predictability for relapse required combined testing, and they were 54 and 60%, respectively. Antibody status remained stable in 60% of patients during 127 +/- 9 months of follow-up, and antibodies to soluble liver antigen/liver pancreas were less labile than antibodies to chromatin (frequency of status change, 4 versus 22%). None of the antibodies were associated with treatment failure, death from hepatic failure or requirement for liver transplantation.

CONCLUSIONS

Antibodies to chromatin and soluble liver antigen/liver pancreas are associated with relapse after corticosteroid withdrawal, and they may be useful prognostic markers. Combined testing improves but does not eliminate deficiencies in sensitivity, predictability and durability.

Significance of antibodies to soluble liver antigen/liver pancreas: a large French study

BACKGROUND

Antibodies to soluble liver antigen (SLA)/liver pancreas (LP) are generally considered as highly specific diagnostic markers of type 1 auto-immune hepatitis (AIH-1), and are particularly useful in patients without conventional antibodies. However, the presence of anti-SLA/LP in type 2 auto-immune hepatitis (AIH-2), primary sclerosing cholangitis (PSC) and hepatitis C has recently been reported. The aim was thus to describe the characteristics of anti-SLA/LP-positive patients in the largest series reported to date.

METHODS

Sera were selected from the period between 1998 and 2005, based on the presence of antibodies to SLA/LP detected by two methods. The clinical status of patients was determined from their medical records.

RESULTS

Eighty-one anti-SLA/LP-positive patients with available clinical data were included: 89% (72/81) had a diagnosis of AIH-1, including 10 (12%) associated with cholestatic diseases (primary biliary cirrhosis in seven cases and PSC in three cases). Six patients (7%) suffered from another liver disease: hepatitis C (n=3) and drug-induced hepatitis (n=3). No specific diagnosis was made in three patients.

CONCLUSIONS

Antibodies to SLA/LP are of a major diagnostic value for AIH-1, including paediatric forms and overlap syndromes with cholestatic diseases, but are not found in association with anti-liver/kidney/microsome type 1 or antibodies to liver cytosol type 1. They are rarely present in other liver diseases such as hepatitis C and drug-induced hepatitis.

Features and consequences of untreated type 1 autoimmune hepatitis

BACKGROUND/AIM

The existence of a mild form of autoimmune hepatitis that does not require treatment remains controversial. The aim of this study was to determine the existence, characteristics and outcome of this form.

METHODS

Untreated patients with type 1 autoimmune hepatitis who did not satisfy pre-established criteria for severe disease were identified retrospectively and compared with treated patients.

RESULTS

Twenty-one of 282 patients (7%) who were evaluated during a 32-year period did not receive corticosteroid treatment. These asymptomatic patients constituted 15% of 137 patients who satisfied similar criteria for mild disease. Untreated patients with mild disease were indistinguishable from 116 treated patients with mild disease, and they differed from 145 treated patients with severe disease only by the pre-established features that defined disease severity. The eight untreated patients with follow-up assessments satisfied remission criteria less commonly than treated patients with mild or severe disease during 77+/-31 months of observation (12 vs 63%, P=0.006), and they had a lower 10-year survival (67 vs 98%, P=0.01). Four patients did improve spontaneously albeit short of remission criteria and remained well for 28+/-15 months (range, 5-73 months). Four patients worsened during 125+/-51 months of observation (range, 32-239 months), including two of three patients with cirrhosis who died of liver failure.

CONCLUSIONS

Mild type 1 autoimmune hepatitis does exist, and it may be as frequent as severe disease. Untreated patients with mild disease can improve spontaneously, but there are no confident indices by which to identify this subgroup and justify withholding treatment.

Current and future treatments of autoimmune hepatitis

Corticosteroid therapy induces clinical, laboratory and histological improvements in 80% of patients with autoimmune hepatitis. Prednisone, alone or at a lower dose in combination with azathioprine, increases the 20-year life expectancy to 80% and prevents or reduces hepatic fibrosis in 79% of patients. The combination regimen is preferred and treatment should be considered in all patients with active disease. The duration of therapy is finite and the medication should be discontinued after resolution of all manifestations of inflammatory activity, including the histological changes. Relapse after drug withdrawal occurs in 50-79% of patients, and it should be treated with long-term azathioprine (2 mg/kg daily). Salvage therapies for individuals intolerant of or refractory to the conventional regimens include high-dose corticosteroids, with or without high-dose azathioprine, 6-mercaptopurine, mycophenolate mofetil, tacrolimus or ciclosporin. Liver transplantation should be considered in patients with hepatic failure unresponsive to corticosteroid treatment, decompensated cirrhosis with a Model for End-Stage Liver Disease score of at least 15 points, or hepatocellular carcinoma that meets transplantation criteria. Autoimmune hepatitis recurs after transplantation in at least 17% of patients, and it typically improves after adjustments in the immunosuppressive regimen. Future therapies are likely to include mesenchymal stem cell transplantation, adoptive transfer of T regulatory cells, and cytokine manipulation. The emergence of new treatments will require the development of a collaborative network of clinical and basic investigators, as the complexity and specificity of current management problems require solutions that exceed the capabilities of single institutions.

HLA and autoimmune digestive disease: a clinically oriented review for gastroenterologists

OBJECTIVES

The human leukocyte antigen (HLA) system includes genes involved in graft-vs-host rejection and in immune response. The discovery that HLAs are associated with several diseases led to appealing developments both in basic biomedical research and in clinical medicine, and offered the opportunity to improve the understanding of pathogenesis and classification of diseases, as well as to provide diagnostic and prognostic indicators. The aim of this article is to review the association between HLA alleles and autoimmune digestive disease and its current relationship with modern HLA nomenclature and clinical practice.

METHODS

Articles dealing with the association between HLAs and autoimmune digestive disease (including celiac disease, inflammatory bowel disease, autoimmune hepatitis, sclerosing cholangitis and primary biliary cirrhosis) were searched for using Pubmed and SCOPUS databases from earliest records to January 2008.

RESULTS

The review has provided two sections. In the first, we explain the basic principles of HLA structure, function, and nomenclature, as an introduction to the second section, which describes current associations between HLA alleles and digestive diseases. The clinical implications of each HLA association are critically discussed. Actually, a clinical role for HLA typing is suggested for only a few conditions, e.g., celiac disease.

CONCLUSIONS

The knowledge of current HLA nomenclature and of its association with some digestive diseases such as celiac disease can be useful in clinical practice for diagnostic and prognostic purposes. This can avoid improper HLA typing as well as stressing the need for further studies on other possible clinical applications.

Genetic factors affecting the occurrence, clinical phenotype, and outcome of autoimmune hepatitis

Autoimmune hepatitis is a polygenic disorder of unknown cause in which the genetic risk factors that affect occurrence, clinical phenotype, severity, and outcome still are being clarified. The susceptibility alleles in white North American and northern European patients reside on the DRB1 gene, and they are DRB1*0301 and DRB1*0401. These alleles encode a 6 amino acid sequence at positions 67-72 in the DRbeta polypeptide chain of the class II molecules of the major histocompatibility complex. This sequence is associated with susceptibility, and lysine at position DRbeta71 is the key determinant. Molecular mimicry between foreign and self-antigens may explain the loss of self-tolerance and the occurrence of concurrent immune diseases in anatomically distant organs. Disease severity is associated with the number of alleles encoding lysine at DRbeta71 (gene dose) and the number of polymorphisms, including those of the tumor necrosis factor-alpha gene, cytotoxic T lymphocyte antigen-4 gene, and tumor necrosis factor-receptor superfamily gene, that can modify the immune response. Individuals in different geographic regions may have different susceptibility alleles that reflect indigenous triggering antigens, and these may provide clues to the etiologic agent. Knowledge of the genetic predispositions for autoimmune hepatitis may elucidate pathogenic mechanisms, identify etiologic agents, characterize susceptible populations, foresee outcomes, and target new therapies. These lessons may be applicable to autoimmune disease in general.

Autoimmune hepatitis. Part A: pathogenesis

Autoimmune hepatitis is a consequence of a triggering antigen and genetic factors that favor the presentation of autoantigens, polymorphisms that affect immunocyte activation and durability, cytokine alterations that promote proliferation of liver-infiltrating cytotoxic T cells, and perturbations in the number and function of immune-regulatory cell populations, including T regulatory cells and natural killer T cells. The triggering epitope is probably a short sequence peptide that is common in multiple infectious or toxic agents. Homologies between this epitope and self-antigens (molecular mimicry) may stimulate humoral and cellular responses that are cross-reactive. Sensitized immunocytes extend and perpetuate the inflammation through imprecise targeting of self-antigens that resemble foreign antigens (promiscuous behavior). The occurrence and clinical phenotype of the disease may relate to genetic susceptibility factors that favor protracted exposure to indigenous etiological agents, and these genetic factors can vary in different geographical regions and ethnic groups. The clinical phenotype within a population can be modified further by genetic polymorphisms that are not disease specific and that affect immunocyte activation, differentiation, proliferation and programmed death (apoptosis). Autoimmune hepatitis is a model of autoreactivity that reflects multiple disturbances in the counter-regulatory mechanisms essential for immune homeostasis.

Autoimmune hepatitis. Part B: diagnosis

Diagnostic criteria have been codified by the International Autoimmune Hepatitis Group, and a scoring system can quantify the strength of the diagnosis and over-ride the impact of absent or inconsistent features. The absence of a definable etiologic agent and precise diagnostic test, implies that the diagnosis may be missed or misapplied. Centrilobular (zone 3) necrosis may be an early form of autoimmune hepatitis and this pattern can transform to the classical pattern of interface hepatitis. An acute severe or fulminant presentation is possible, and different ethnic groups may have different manifestations and outcomes. Asymptomatic patients at presentation commonly become symptomatic, and treatment decisions must be based on objective features of disease severity and not the presence or absence of symptoms. Concurrent autoimmune diseases are frequent, and they may constitute an autoimmune polyglandular syndrome associated with a single gene mutation. Emerging autoantibodies of possible prognostic value are antibodies to soluble liver antigen/liver pancreas, asialoglycoprotein receptor, actin, and liver cytosol type 1. HLA DRB1*03, *04, *03-*04, *07, *13 and DQB1*02 are associated with the occurrence, clinical phenotype and outcome of autoimmune hepatitis. Variant syndromes should be suspected if cholestatic features are prominent and conventional treatment is ineffective.

Autoimmune hepatitis in children: diagnosis, pathology and treatment

Autoimmune hepatitis (AIH) is characterized by progressive inflammation of the liver and destruction of liver parenchyma. Rare in absolute terms, it is nevertheless an important cause of noninfectious chronic liver disease in children. In many ways, the diagnosis and treatment of children with AIH has changed little over the last 10 years. However, in recent years, steady progress in defining the genetic, immunologic and potential environmental triggers that underlie this disease, in addition to increasing experience with a wider array of therapeutic agents, promises to expand our understanding and ability to treat AIH effectively. This review will summarize the current clinical and pathophysiological understanding of AIH in children, along with therapeutic options.

Evidence of a genetic basis for the different geographic occurrences of liver/kidney microsomal antibody type 1 in hepatitis C

Antibodies to liver/kidney microsome type 1 occur in Italian patients with hepatitis C, but rarely develop in North American patients. Our goals were to compare the frequencies of the HLA markers associated with autoimmune expression in Italian and North American patients with chronic hepatitis C and to determine genetic bases for regional differences in antibody production. HLA B8, DR3, DR4, DR7, DR11, DR13, DQ2, and the B8-DR3-DQ2 haplotype were determined by microlymphocytotoxicity and polymerase chain reaction in 105 Italian patients (50 with microsomal antibodies), 100 North American patients (none with microsomal antibodies), and Italian and North American healthy control subjects. Italian patients with microsomal antibodies differed from North American patients without these antibodies by having a higher frequency of HLA DR7 (54% vs. 27%, P=0.002). HLA DR7 occurred more frequently in seropositive Italian patients than in seronegative counterparts (54% vs. 11% P < 0.0001), Italian healthy control subjects (54% vs. 29%, P=0.0009), and North American healthy control subjects (54% vs. 19%, P < 0.0001). The frequency of HLA DR7 was similar in North American patients and controls (27% vs. 19%, P=0.2), but it was lower than in Italian controls (19% vs. 29%, P=0.059). Seropositive Italian patients had a lower frequency of HLA DR11 than seronegative Italian patients and Italian controls (18% vs. 34%, P=0.07, and 18% vs. 35%, P=0.02, respectively). In contrast to seropositive Italian patients, North American patients had HLA DR4 (30% vs. 12%, P=0.02), HLA DR13 (29% vs. 10%, P=0.01), and the B8-DR3-DQ2 haplotype (23% vs. 6%, P=0.01) more often. Similarly, HLA DR4 and the B8-DR3-DQ2 phenotype were more frequent in North American patients than in Italian controls (30% vs. 16%, P=0.005, and 23% vs. 7%, P=0.00002, respectively). HLA DR7 is associated with the development of microsomal antibodies in Italian patients with chronic hepatitis C. The lower frequency of HLA DR7 in North America could contribute to the rarity of these antibodies in this region. HLA DR11 may be protective against the development of microsomal antibodies in Italian patients, whereas HLA DR4, HLA DR13, and the B8-DR3-DQ2 haplotype may be protective in North American patients.

Type 1 autoimmune hepatitis in Taiwan: diagnosis using the revised criteria of the International Autoimmune Hepatitis Group

Autoimmune hepatitis (AIH) is rare in Asian countries compared to the West, and an exceptionally low prevalence was noted previously in Taiwan. Using the revised criteria of the IAIHG, 48 cases of AIH patients were diagnosed. All patients were consecutively diagnosed over a period of 5 years. Detailed medical histories including disease onset, hepatitis B and C, alcohol, drugs, blood transfusion, and family history of autoimmune disease were recorded. Clinical manifestations, result of steroid therapy, outcome, and survival rate were investigated and analyzed. Clinical data on AIH patients with cirrhosis and without cirrhosis were compared and analyzed for their outcome. The statistical methods used were Fisher's exact test, Wilcoxon rank sum test, and Kaplan-Meier curve. Forty-eight patients were diagnosed as AIH type 1, with a median age of 58 years and a female:male ratio of 37:11. The most common clinical features at presentation were fatigue, jaundice, and anorexia. Ninety-eight percent of patients were ANA positive, and most of the patients showed elevated values of AST, ALT, serum globulin, and bilirubin. A substantial proportion of patients presented with poor liver function at entry and 35% of patients had liver cirrhosis, with relatively prolonged PT (P=0.001) and poorer outcome (P=0.005) compared to the noncirrhotics. As a whole there was a favorable treatment response and the overall survival rate was 85%. We conclude that the incidence of AIH in Taiwan is much higher than previously presumed and AIH type 1 is the predominant type of the disease. Although a substantial proportion of AIH patients presented with poor hepatic function at entry, as a whole there was a favorable clinical outcome.

Frequency and significance of antibodies to cyclic citrullinated peptide in type 1 autoimmune hepatitis

OBJECTIVES

Determine the frequency, clinical phenotype, and prognostic implications of antibodies against cyclic citrullinated peptides in patients with type 1 autoimmune hepatitis.

METHODS

Three hundred and ninety-five serum samples from 179 patients were tested by enzyme-linked immunosorbent assay, and findings correlated with clinical and histological features, frequency of HLA DR3 and DR4, and treatment outcome.

RESULTS

Twenty patients (11%) had antibodies against cyclic citrullinated peptides. Seropositivity was associated with a higher frequency of rheumatoid arthritis (RA) (25 vs. 0%, P < 0.001). Patients with antibodies against cyclic citrullinated peptides also had a significantly greater occurrence of histological cirrhosis at presentation (47 vs. 20%, P = 0.01) and death from hepatic failure than seronegative patients (25 vs. 9%, P = 0.04). Cirrhosis at presentation occurred more commonly in the patients with antibodies against cyclic citrullinated peptides and RA than in the other patients (100 vs. 21%, P = 0.005).

CONCLUSIONS

Antibodies against cyclic citrullinated peptides occur in a subgroup of patients with type 1 autoimmune hepatitis who have a greater occurrence of cirrhosis at presentation and death from hepatic failure. Their presence with RA at accession characterizes a subgroup with cirrhosis.

Autoimmune hepatitis, from mechanisms to therapy

In 1950, Waldenström was the first to describe a chronic form of hepatitis in young women. Subsequently, the disease was found to be associated with other autoimmune syndromes and was later termed "lupoid hepatitis" because of the presence of antinuclear antibodies. In 1965, it became designated by Mackay et al. as "autoimmune hepatitis" at an international meeting, at which the general concept of autoimmunity was endorsed by the scientific community. In the early 1960s and 1970s, the value of immunosuppressive therapy with glucocorticoids and/or azathioprine was well documented in several studies. The original association of autoimmune hepatitis (AIH) and HLA alleles, which has remarkably stood the test of time, was published in 1972. In the 1970s and 1980s, several autoantibodies were identified in patients with autoimmune hepatitis directed against proteins of the endoplasmatic reticulum expressed in liver and kidney and against soluble liver antigens. Subsequently, the molecular targets of these antibodies were identified and more precisely characterized. In the last two decades many additional pieces of the AIH puzzle have been collected leading to the identification of additional antibodies and genes associated with AIH and to the emergence of new therapeutic agents. Meanwhile, the immunoserological and genetic heterogeneity of AIH is well established and it has become obvious that clinical manifestations, disease behavior, and treatment outcome may vary by racial groups, geographical regions and genetic predisposition. Currently, the International Autoimmune hepatitis group is endorsing multi-center collaborative studies to more precisely define the features at disease presentation and to define prognostic indices and appropriate treatment algorithms. Given the importance of serological testing, the IAHG is also working on guidelines and procedures for more reliable and standardized testing of autoantibodies.

Autoantibodies in autoimmune liver disease

Autoantibodies indicate an immune reactive state, but in liver disease they lack pathogenicity and disease specificity. Antinuclear antibodies, smooth muscle antibodies, antibodies to liver/kidney microsome type 1, antimitochondrial antibodies, and perinuclear antineutrophil cytoplasmic antibodies constitute the standard serological repertoire that should be assessed in all liver diseases of undetermined cause. Antibodies to soluble liver antigen/liver pancreas, asialoglycoprotein receptor, actin, liver cytosol type 1, nuclear antigens specific to primary biliary cirrhosis, and pore complex antigens constitute an investigational repertoire that promises to have prognostic and diagnostic value. These autoantibodies may emerge as predictors of treatment response and outcome. Antibodies to histones, doubled-stranded DNA, chromatin, and lactoferrin constitute a supplemental repertoire, and they support the immune nature of the liver disease. Final diagnoses and treatment strategies do not depend solely on serological markers. Autoantibodies are floating variables, and their behavior does not correlate closely with disease activity. There are no minimum levels of significant seropositivity, especially in children. Over-interpretation is the major pitfall in the clinical application of the serological results. New autoantibodies will emerge as the search for target antigens and key pathogenic pathways continues.

Regulation of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis: contrasting effects of HLA-DR3 and the shared epitope alleles

OBJECTIVE

To examine the association between HLA-DRB1 alleles and the production of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) autoantibodies in patients with rheumatoid arthritis (RA).

METHODS

We studied 1,723 Caucasian RA patients enrolled in the North American Rheumatoid Arthritis Consortium (NARAC) family cohort and the Study of New Onset Rheumatoid Arthritis (SONORA) cohort. All patients were tested for anti-CCP antibodies (by enzyme-linked immunosorbent assay), RF (by nephelometry), and HLA-DR genotype (by polymerase chain reaction and sequence-specific oligonucleotide hybridization).

RESULTS

When controlled for the presence of RF, anti-CCP positivity was strongly associated with the HLA-DRB1 shared epitope (SE). In RF+ patients, the presence of the SE was very significantly associated with anti-CCP positivity, with an odds ratio (OR) of 5.8 and a 95% confidence interval (95% CI) of 4.1-8.3. This relationship was also seen in RF- patients (OR 3.1 [95% CI 1.8-5.3]). In contrast, RF positivity was not significantly associated with presence of the SE independently of anti-CCP antibodies. Strikingly, HLA-DRB1*03 was strongly associated with reduced anti-CCP titers, even after controlling for the presence of the SE and restricting the analysis to anti-CCP+ patients. HLA-DR3 was also associated with anti-CCP- RA in our population.

CONCLUSION

The HLA-DRB1 SE is strongly associated with the production of anti-CCP antibodies, but not RF. In contrast, HLA-DR3 alleles are associated with anti-CCP- disease and with lower levels of anti-CCP antibodies, even when controlling for the SE. These data emphasize the complexity of the genetic effects of the major histocompatibility complex on the RA phenotype.

Anti-tRNP(ser)sec/SLA/LP autoantibodies. Comparative study using in-house ELISA with a recombinant 48.8 kDa protein, immunoblot, and analysis of immunoprecipitated RNAs

BACKGROUND

Antibodies against tRNP((ser)sec) (ribonucleoproteins, RNP) have been described in our laboratory as markers of poor outcome in type 1 autoimmune hepatitis (AIH). The antigenic protein has been sequenced and cloned as a 48.8 kDa protein and identified with soluble liver antigen (SLA) and liver-pancreas (LP) antigen. The aim of this paper was to determine the best assay by which to detect these antibodies in type 1 AIH.

METHODS

A simple and reliable enzyme linked immunoassay based on prokaryotically expressed protein was compared with an immunoblot assay using prokaryotically- and eukaryotically-expressed proteins and an assay based on immunoprecipitated RNAs from HeLa cell extracts. Eighty-one sera from 58 patients with type 1 AIH, 168 sera from patients with autoimmune diseases or chronic hepatitis C, and 60 sera from healthy subjects were similarly tested.

RESULTS

The specificity of the assays was 100%, but the frequency of seropositivity was higher in the assay based on immunoprecipitated RNAs (44.4%) than in the enzyme-linked immunosorbent assay (ELISA) (16%) and the immunoblot assay with prokaryotically (12.34%) and eukaryotically (14.8%)-expressed protein. There were no clinical differences between the patients positive by ELISA, immunoblot assay, or immunoprecipitated RNAs.

CONCLUSIONS

These results suggest that the analysis of the immunoprecipitated RNAs is the most useful, sensitive and specific method to detect anti-tRNP((ser)sec)/SLA/LP autoantibodies.

Treatment challenges and investigational opportunities in autoimmune hepatitis

New drugs and advances in molecular biology afford opportunities to upgrade the treatment of autoimmune hepatitis. The aims of this study were to define treatment problems, identify possible solutions, and stimulate investigations to improve patient care. A clinical subcommittee of the International Autoimmune Hepatitis Group reviewed current management difficulties and proposed corrective actions. The assessment of new front-line and salvage therapies for adults and children were given top priority. Cyclosporine and mycophenolate mofetil were endorsed as drugs worthy of rigorous study in severe disease, and budesonide was endorsed for study as front-line therapy in mild disease. Diagnostic criteria and treatment regimens for children required codification, and pharmacokinetic studies were encouraged to develop optimal dosing schedules based on therapeutic ranges. Collaborative efforts were proposed to help understand racial, geographical, and genetic factors affecting outcome and to establish definitions and therapies for variant syndromes and graft dysfunction after transplantation. The development of experimental animal models was deemed essential for the study of site-specific molecular interventions, and gene therapy was endorsed as a means of bolstering reparative processes. In conclusion, evolving pharmacological and technical advances promise to improve the treatment of autoimmune hepatitis, and investigations of these advances are timely, feasible, and necessary.

Autoantibodies and autoantigens in autoimmune hepatitis: important tools in clinical practice and to study pathogenesis of the disease

Autoimmune hepatitis (AIH) is a chronic necroinflammatory disease of the liver characterized by hypergammaglobulinemia, characteristic autoantibodies, association with HLA DR3 or DR4 and a favorable response to immunosuppressive treatment. The etiology is unknown. The detection of non-organ and liver-related autoantibodies remains the hallmark for the diagnosis of the disease in the absence of viral, metabolic, genetic, and toxic etiology of chronic hepatitis or hepatic injury. The current classification of AIH and the several autoantibodies/target-autoantigens found in this disease are reported. Current aspects on the significance of these markers in the differential diagnosis and the study of pathogenesis of AIH are also stated. AIH is subdivided into two major types; AIH type 1 (AIH-1) and type 2 (AIH-2). AIH-1 is characterized by the detection of smooth muscle autoantibodies (SMA) and/or antinuclear antibodies (ANA). Determination of antineutrophil cytoplasmic autoantibodies (ANCA), antibodies against the asialoglycoprotein receptor (anti-ASGP-R) and antibodies against to soluble liver antigens or liver-pancreas (anti-SLA/LP) may be useful for the identification of patients who are seronegative for ANA/SMA. AIH-2 is characterized by the presence of specific autoantibodies against liver and kidney microsomal antigens (anti-LKM type 1 or infrequently anti-LKM type 3) and/or autoantibodies against liver cytosol 1 antigen (anti-LC1). Anti-LKM-1 and anti-LKM-3 autoantibodies are also detected in some patients with chronic hepatitis C (HCV) and chronic hepatitis D (HDV). Cytochrome P450 2D6 (CYP2D6) has been documented as the major target-autoantigen of anti-LKM-1 autoantibodies in both AIH-2 and HCV infection. Recent convincing data demonstrated the expression of CYP2D6 on the surface of hepatocytes suggesting a pathogenetic role of anti-LKM-1 autoantibodies for the liver damage. Family 1 of UDP-glycuronosyltransferases has been identified as the target-autoantigen of anti-LKM-3. For these reasons the distinction between AIH and chronic viral hepatitis (especially of HCV) is of particular importance. Recently, the molecular target of anti-SLA/LP and anti-LC1 autoantibodies were identified as a 50 kDa UGA-suppressor tRNA-associated protein and a liver specific enzyme, the formiminotransferase cyclodeaminase, respectively. Anti-ASGP-R and anti-LC1 autoantibodies appear to correlate closely with disease severity and response to treatment suggesting a pathogenetic role of these autoantibodies for the hepatocellular injury. In general however, autoantibodies should not be used to monitor treatment, predict AIH activity or outcome. Finally, the current aspects on a specific form of AIH that may develop in some patients with a rare genetic syndrome, the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) are also given. Autoantibodies against liver microsomes (anti-LM) are the specific autoantibodies detected in AIH as a disease component of APECED but also in cases of dihydralazine-induced hepatitis. Cytochrome P450 1A2 has been identified as the target-autoantigen of anti-LM autoantibodies in both APECED-related AIH and dihydralazine-induced hepatitis. The latter may indicate that similar autoimmune pathogenetic mechanisms can lead to liver injury in susceptible individuals irrespective of the primary defect. Characterization of the autoantigen-autoantibody repertoire continues to be an attractive and important tool to get access to the correct diagnosis and to gain insight into the as yet unresolved mystery of how hepatic tolerance is given up and AIH ensues.

Long-term outcome of liver transplantation for autoimmune hepatitis

BACKGROUND

Liver transplantation is the final therapeutic option for about 10% of patients with autoimmune hepatitis (AIH) who do not respond to medical therapy. The aim of this study was to evaluate the long-term outcome in serologically defined subgroups of AIH after transplantation.

METHODS

Pre- and post-transplantation data of 28 patients with AIH transplanted between 1987 and 1999 were retrospectively analyzed and compared with 24 patients, who underwent liver transplantation because of Wilson's disease and glycogen storage disease type 1.

RESULTS

Serological analyses identified patients with AIH type 1 (n = 13), type 2 (n = 5), and type 3 (n = 10). The 5-yr patient survival rate after liver transplantation was 78.2%, which was not significantly different from the control group. Six AIH patients and four control patients required re-transplantation because of initial non-function, chronic rejection or AIH recurrence. Patients transplanted for AIH (88%) had more episodes of acute rejection when compared with patients transplanted for genetic liver diseases (50%). Clinical and histological features of chronic rejection were present in four patients, which did not differ significantly from the controls. Recurrence of AIH was diagnosed in nine patients (32%) based upon the presence of autoantibodies, increased gamma-globulins, steroid dependency, and histological evidence of chronic hepatitis. These combined features were not found in any of the controls.

CONCLUSIONS

Our data do not suggest that AIH subtypes influence prognosis after liver transplantation. Despite a high frequency of acute cellular rejection episodes and disease recurrence, transplantation for AIH has a 5-yr survival rate, which does not differ from that observed in patients transplanted for genetic liver diseases.

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Autoantibodies in the diagnosis and management of liver disease

Autoantibodies are nonpathogenic manifestations of immune reactivity, and they may occur in acute and chronic liver diseases. Autoantibodies may be consequences rather than causes of the liver injury, and they should be regarded as diagnostic clues rather than etiologic markers. Conventional autoantibodies used in the categorization of autoimmune liver disease are antinuclear antibodies, smooth muscle antibodies, antibodies to liver/kidney microsome type 1, antimitochondrial antibodies, and atypical perinuclear anti-neutrophil cytoplasmic antibodies. Ancillary autoantibodies that enhance diagnostic specificity, have prognostic connotation, or direct treatment are antibodies to endomysium, tissue transglutaminase, histones, doubled-stranded DNA, and actin. Autoantibodies that have an emerging diagnostic and prognostic significance are antibodies to soluble liver antigen/liver pancreas, asialoglycoprotein receptor, liver cytosol type 1, and nuclear pore complex antigens. Autoantibodies of uncertain clinical value that remain under investigation are antibodies to chromatin, lactoferrin, and Saccharomyces cervisiae. Continued recognition and characterization of autoantibodies should improve diagnostic precision, provide prognostic indices, and elucidate target autoantigens. These advances may in turn clarify pathogenic mechanisms, facilitate the development of animal models, and generate novel site-specific therapies.

Autoimmune liver disease

Autoimmune hepatitis can affect diverse ethnic groups, and its clinical expression and outcome can vary accordingly. An asymptomatic presentation may identify patients who respond more readily to medication. Celiac sprue is important to recognize and treat by gluten restriction. Centrilobular necrosis and coincidental destructive cholangitis do not preclude the diagnosis, and antibodies to soluble liver antigen/liver pancreas may identify patients susceptible to relapse. Women, who have non-DRB1*0401 DR4 alleles more commonly than do men, may respond to a diverse range of autoantigens. DRB1*1301 is associated with autoimmune hepatitis in Brazil, especially among children, and it may favor an indigenous triggering agent. Variant syndromes are heterogenous conditions that probably reflect referral biases, and molecular mimicry between foreign and self-antigens is the basis for most theories of pathogenesis. Immunosuppressive medications (eg, cyclosporine, mycophenolate mofetil) have been used empirically with success, and recurrent and de novo disease after liver transplantation must be considered in all patients with graft dysfunction.

Histological features associated with relapse after corticosteroid withdrawal in type 1 autoimmune hepatitis

Relapse of type 1 autoimmune hepatitis after drug withdrawal may relate to incomplete histological improvement during corticosteroid therapy and/or persistence of pathogenic mechanisms.

AIM

Determine the histological features prior to drug withdrawal that are associated with relapse in patients satisfying pre-established clinical, laboratory, and histological criteria for remission and relapsing after corticosteroid withdrawal.

METHODS

One hundred liver tissue samples obtained immediately prior to corticosteroid withdrawal from 88 patients who had previously satisfied criteria for histological remission were reviewed retrospectively.

RESULTS

Histological findings in the patients who relapsed were similar to those in the patients who sustained remission in regard to histological activity index (1.7 +/- 0.1 versus 1.6 +/- 0.2, P = 0.6), fibrosis score (2.6 +/- 0.3 versus 2.3 +/- 0.4, P = 0.5), and frequencies of interface hepatitis (36% versus 20%, P = 0.2), cirrhosis (21% versus 17%, P = 0.8), and normal or near normal tissue (9% versus 7%, P > 0.9). Only the presence of portal plasma cells was associated with relapse (31% versus 7%, P = 0.01). The positive predictability of portal plasma cell infiltration for relapse was 92%, but its sensitivity was only 31%.

CONCLUSIONS

Portal plasma cell infiltration is predictive of relapse after drug withdrawal in tissue specimens already satisfying criteria for remission. Portal plasma cell infiltration may be indicative of an active antibody-dependent pathogenic mechanism. Its low sensitivity for relapse indicates the need for other complementary predictors of outcome.

Transition of care between paediatric and adult gastroenterology. Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a rare chronic disease of the liver with an excellent prognosis under medical therapy capable of reaching complete remission. The diagnosis of AIH relies on the exclusion of viral, metabolic, genetic and toxic aetiologies of chronic hepatitis, or hepatic injury. Autoantibodies contribute to the diagnosis of AIH and have led to the serological subclassification into three distinct types. Also, immunogenetic associations suggest heterogeneity of the syndrome of AIH. Treatment is not based on serological types but is uniformly employed for all subtypes of AIH. Although 90% of patients respond to treatment, immunosuppressive drugs used in transplant medicine have been employed for patients with treatment failure. New drugs, such as budenoside, are being evaluated for the long-term treatment of AIH with a reduction in steroid side-effects. Liver transplantation is an established treatment option for patients who fail to reach remission and progress to cirrhosis and liver failure. In Europe, about 4% of cirrhotic patients with the diagnosis of AIH undergo transplantation. The diagnosis and awareness of the disease is designed to reduce mortality and morbidity.

Genetic effects on susceptibility, clinical expression, and treatment outcome of type 1 autoimmune hepatitis

Currently, three genetic factors have been short-listed as possible modulators of susceptibility and severity in type 1 AIH. They are female sex, HLA DRB alleles encoding lysine at position DR beta 71, and the CTLA4*G allele. The fourth association (i.e., TNFRSF6) remains to be confirmed. There are many other candidates to investigate. Current hypotheses suggest that the autoimmune genotype will include multiple (some linked, others discrete) loci which make a permissive background. Not all "at risk" individuals will develop clinical disease, and selection will depend on the interaction of this "permissive gene pool" (i.e., the host) with the environment. The resulting autoimmune phenotype will depend on gene dose and gene interaction. The human genome project has presented medical science with the challenge to identify the genes that determine common human diseases, including autoimmunity [1]. Although type 1 AIH is considerably less common than diabetes or RA, it may serve as a useful model for other autoimmune diseases. Diagnosis depends on histologic findings, and liver biopsy examinations are part of the usual assessment strategy in type 1 AIH. The availability of these tissue specimens provides a clear basis for monitoring disease progression and may permit investigators to study the impact of genetic polymorphism on disease activity. The emergence of high throughput technologies will significantly enhance our ability to study the interactions between constellations of polymorphic genes and both disease expression and behavior. An abundance of polymorphism is found in the genome. In many diseases, functional studies and genome scanning have helped revise and reduce the list of candidates. Affected families are rare in type 1 AIH, and patients are at risk if corticosteroid treatment is withheld. Under these circumstances, genetic studies may be the most practical, low risk means to investigate the pathogenesis of type 1 AIH and many other autoimmune diseases.