Autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterised histologically by interface hepatitis, and serologically by the presence of non-organ and liver specific autoantibodies and increased levels of immunoglobulin G. Its onset is often ill-defined, frequently mimicing acute hepatitis. AIH usually responds to immunosuppressive treatment, which should be instituted as soon as diagnosis is made. Two types of AIH are recognized according to seropositivity for smooth muscle and/or antinuclear antibody (SMA/ANA, type 1 AIH) or liver kidney microsomal type 1 antibody (LKM1, type 2 AIH). There is a female predominance in both. LKM1 positive patients tend to present more acutely, at a younger age and commonly have immunoglobulin A deficiency, while duration of symptoms before diagnosis, clinical signs, family history of autoimmunity, presence of associated autoimmune disorders, response to treatment and long-term prognosis are similar in the 2 groups. Susceptibility to AIH type 1 is conferred by possession of HLA DR3 and DR4, while to AIH type 2 by possession of HLA DR7. Liver damage is likely to derive from an immune reaction to liver cell antigens, possibly triggered by a mechanism of molecular mimicry, where immune responses to external pathogens, e.g. viruses, become directed towards structurally similar self-components. In AIH this process would be perpetuated by impairment in immune regulation.     

Autoimmune hepatitis in childhood

Autoimmune hepatitis (AIH) is a generally progressive inflammatory liver disease of unknown etiology that occurs in adults and children. Although the peak age of incidence is in prepubertal girls, AIH has been diagnosed as early 6 months of age. Two types of AIH are recognized according to the nature of the autoantibody detected in children at the time of diagnosis. The diagnosis of AIH is based on histological abnormalities, characteristic clinical and biochemical findings, and abnormal levels of serum globulin due almost exclusively to markedly increased immunoglobulin G including various autoantibodies. A genetic predisposition is suggested by the increase frequency of human leukocyte antigen (HLA) haplotypes HLA-B8/DR3, and allotypes DR3 and DR4. However, the incidence of these HLA types is different in each country.Proposed triggers of AIH that may initiate the inflammatory process include some viral infections and some drugs. There is much information about adults with AIH, however, little information on AIH in children, especially in Japanese children. To clarify the clinicohistological features of AIH in Japanese children, we analyzed the clinical, pathological features and response to treatment in 12 Japanese children with AIH. Furthermore, we discuss several problems for diagnosis and treatment for AIH in children.     

Update on Autoimmune Hepatitis

Autoimmune hepatitis (AIH), a liver disorder affecting both children and adults, is characterized by inflammatory liver histology, elevated transaminase levels, circulating nonorganspecific autoantibodies, and increased levels of immunoglobulin G, in the absence of a known etiology. Two types of AIH are recognized according to seropositivity: smooth muscle antibody and/or antinuclear antibody define AIH type 1 and antibodies to liver-kidney microsome type 1 and/or liver cytosol type 1 define AIH type 2. AIH type 1 affects both adults and children, while AIH type 2 is mainly a paediatric disease, though it does occasionally affects young adults. AIH should be considered during the diagnostic workup of any patient with increased liver enzyme levels. AIH is exquisitely responsive to immunosuppressive treatment with prednisolone with or without azathioprine, with symptom free long-term survival for the majority of patients. For those who do not respond to standard treatment, or who are difficult-to-treat, mycophenolate mofetil and, in the absence of a response, calcineurin inhibitors should be tried in addition to steroids. 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 T-cells, although recent studies support the involvement of diverse populations, including Th17 cells. 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 antigenspecific regulatory T-cells, which ultimately aim at restoring tolerance to liver-derived antigens.     

Clinico-laboratory study on children with auto-immune hepatitis in Upper Egypt

Background and study aimsAuto-immune hepatitis (AIH) in children is a rare chronic progressive liver disorder. It is characterised serologically by high aminotransferase levels, elevated immunoglobulin G (IgG) and the presence of autoantibodies. AIH is divided into two types according to the autoantibody profile. This study aims to assess frequency, clinical manifestations, biochemical features and outcome of AIH in children attending Assuit University Hospitals in Upper Egypt with acute icteric hepatitis and seronegative viral markers (anti-hepatitis A virus (HAV) IgM, HbsAg, anti-hepatitis C virus (anti-HCV) Ab).Patients and methodsThe study includes 34 children with AIH, diagnosed on the basis of the International Scoring Criteria of Auto-immune Hepatitis, recruited from Assuit University Hospitals, during the period from January 2005 to December 2009. All patients received prednisolone 2 mg kg^–1 day^–1. Follow-up was done for 1 year.ResultsAmong 34 children diagnosed as AIH, 24 were females (70.5%) and 10 were males (29.5%). Jaundice represented the most consistent finding in all patients. According to the autoantibody profile, 25 children were classified as type 1 and nine children were classified as type 2. Corticosteroid therapy was started. Complete remission was observed in 67.6% of patients and partial remission in 17.6%. There was no significant statistical difference in clinical and biochemical features of AIH in patients regarding the response to treatment. Mild side effects of steroid therapy were encountered in 48.2% of patients. After complete withdrawal of corticosteroids, six patients (20.7%) developed relapse.ConclusionAIH type 1 was the main form of AIH in children referred to Assiut University Hospitals. Girls were more affected than boys. AIH type 1 exhibited a more active, ongoing immunologic process. Steroid alone can be used successfully in most cases. Children with AIH type 2 had a higher frequency of relapse after corticosteroid withdrawal. Further studies on a larger number of cases and long-term follow-up are recommended.     

Immunogenetic background of hepatitis B virus infection and autoimmune hepatitis in Japan

Human leucocyte antigen (HLA)-typing was studied in 82 hepatitis B carriers and 15 cases of autoimmune hepatitis (AIH) to elucidate the genetic factors which may associated with the etio-pathogenesis of chronic hepatitis in Japan. There were two types of HLA phenotypes: HLA A2 was associated with the progression of the disease induced by HBV infection, and HLA A26 and DR5 were related to the retardation of the disease. A family study confirmed the strong association of these HLA phenotypes with the disease induced by HBV infection. In the analysis of AIH, HLA DR4 is a risk factor related to susceptibility of Japanese AIH which shows different clinical manifestations compared to HLA-DR3-positive AIH, dominantly observed in Western countries. These results suggest that genetic background as expressed by HLA, is an important factor in restricting the development of type B hepatitis and AIH, and can explain racial differences of disease susceptibility. Part of this study was supported by a grant from the Natinal Study Group on Hepatitis of the Health and Welfare Ministry and a grant from the Department of Education (No. 04670445).     

Genetic distinctions between autoimmune hepatitis in Italy and North America

AIM: Our goals were to analyze the known genetic predispositions for autoimmune hepatitis (AIH) in AIH Italian population and to compare them with North American counterparts. METHODS: Human leukocyte antigens (HLA) B8, C7, DR3, DR4, DR7, DR11, DR13, DQ2 and the B8-DR3-DQ2 phenotype were determined by microlymphocytotoxicity and polymerase chain reaction in 74 Italian patients (57 with type 1 and 17 with type 2 AIH) and 149 North American patients with type 1 AIH, and in adequate controls. RESULTS: B8-DR3-DQ2 occurred more frequently in Italian patients with type 1 AIH than in Italian controls (30% vs 7%, P<0.0001), but less frequently than in North American counterparts (30% vs 48%, P= 0.02). DR4 occurred less frequently in Italian patients with type 1 AIH (23% vs 43%, P= 0.01) and in controls (16% vs 34%, P= 0.0003) than in North American counterparts. No differences were found in alleles' frequency between type 1 and type 2 Italian AIH patients. DR11 had a frequency lower in type 1 Italian AIH patients than controls (17% vs 35%, P= 0.01). CONCLUSION: HLA DR4 is not associated with AIH in Italy. The known HLA risk factors for AIH occur similarly in Italian patients with type 1 and type 2 AIH, and they are less frequent than in North American patients. B8-DR3-DQ2 is the predominant phenotype of type 1 AIH also in Italy, and HLA DR11 may be a regionally distinctive protective factor against type 1 AIH.     

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.     

Type 1 autoimmune hepatitis in Turkish patients: absence of association with HLA B8

BACKGROUND: There is very little information about autoimmune hepatitis (AIH) in populations other than of white European or Japanese descent. GOALS: To investigate the presenting features, immunogenetic background, and response to standard immunosuppressive therapy in native Turkish patients with AIH. METHODS: Retrospective analysis of all patients referred between 1994 and 2000 to our hepatology clinic in Ankara who fulfilled international criteria for definite or probable type 1 or type 2 AIH. RESULTS: Seventeen patients (15 female; median age, 31 years; range, 13-56 years) were identified. All had type 1 AIH. Clinical and laboratory features were broadly similar to those reported for white or Japanese patients. Five had the HLA DR3 allotype and 10 had DR4; however, in contrast to white and Japanese patients, DR4 was not associated with an older age at onset. Importantly, no patient had the B8 allotype (vs. 10.9% in 110 healthy Turkish subjects). Thus, none had the classic A1-B8-DR3 autoimmune haplotype: a major distinction from white individuals. CONCLUSIONS: There appears to be genetic differences in type 1 AIH between Turkish and other populations. Genotyping of Turkish patients to identify alleles that may confer susceptibility or resistance to AIH may progress understanding of the genetic basis of the disease.     

Outcomes in pediatric autoimmune hepatitis

Autoimmune hepatitis (AIH) is a common cause of acute and chronic hepatitis in childhood. Once the diagnosis is established, treatment with corticosteroid or corticosteroid and azathioprine is indicated. Most children with AIH respond to such therapy and experience remission from active disease. Eliminating drug therapy while maintaining remission is the ultimate goal of therapy. The optimal duration of therapy before drug elimination is unclear. Relapse rate is inversely related to therapy duration before drug withdrawal; thus, discontinuing immunosuppressive treatment is considered only after at least 1 to 2 years of complete remission. When applying a slow and systematic approach, many children with AIH can successfully be weaned off immunosuppression completely. Even patients presenting in acute liver failure may avoid liver transplantation with early medical therapy. In about 10% of patients, treatment fails, requiring alternative therapies and/or liver transplantation as liver disease progresses. Less than 10% of children with autoimmune hepatitis die during 10 years of follow-up.     

Autoimmune Hepatitis in a Genetically Susceptible Patient (Is It Triggered by Acute Viral Hepatitis A?)

The pathogenic mechanisms for autoimmune hepatitis (AIH) are not completely known. Susceptibility to AIH is associated with the human leukocyte antigens (HLA) class II: DR3 and DR4. Nevertheless, AIH does not have a strong genetic predisposition, suggesting that other factors are involved. Perhaps the strongest evidence of a viral cause for AIH exists for hepatitis C virus. AIH has been reported to develop rarely after acute infection with hepatitis A virus. We report on a 55-year-old woman in whom AIH developed during the convalescence period of serologically proven acute viral hepatitis type A. HLA class II DRB1*0401, which was reported to be associated with AIH with a moderate coarse and late appearance in life, was found in this patient. Steroid therapy was followed by a complete clinical remission. Our case supports the possibility that acute hepatitis A may trigger the development of AIH in a genetically susceptible subject.     

Hepatitis autoinmune en niños: evolución de 20 casos del norte de México

BackgroundAutoimmune hepatitis (AIH) is a chronic inflammatory disease of the liver with nonspecific clinical manifestations that causes greater liver damage in children than in adults.AimsTo analyze the clinical progression, biochemical profiles, histopathologic changes, and treatment response in 20 children with AIH.Material and methodsA retrospective study was carried out on the variables associated with clinical progression, diagnosis, and treatment response in children seen at the the Unidad Médica de Alta Especialidad (UMAE) No. 71 IMSS in Torreón, Coahuila, Mexico, from 1992 to 2012.ResultsTwenty patients were analyzed, 75% with type 1 AIH (AIH-1) and 25% with type 2 AIH (AIH-2). Girls predominated with a 3:1 ratio of girls to boys. The mean age was 10.07 ± 6.53 years for the AIH-1 cases and 6.75 ± 3.77 years for the AIH-2 cases. There was an association with immunologic diseases in 40% of the patients.The patients in the AIH-2 group had greater biochemical profile alterations and IgA deficiency. Anti-nuclear antibody and anti-smooth muscle antibody were positive in 100% of the patients with AIH-1, and anti-liver kidney microsomal type 1 antibody was positive in 100% of the AIH-2 patients. Liver biopsy revealed interface hepatitis in both groups. The AIH-2 group responded more quickly to treatment, but had a higher recurrence rate.ConclusionsAutoimmune hepatitis in the pediatric patient should be suspected in order to make an early diagnosis and thereby establish opportune treatment. Determining the type of AIH is necessary for making adequate diagnosis and for achieving a better outcome in relation to recurrence and complication rates.     

Relationship between human leukocyte antigen-DRB1 and autoimmune hepatitis type I in Chinese patients

AIM: To analyze the association of human leukocyte antigen (HLA)-DRB1 with autoimmune hepatitis type I (AIH) among Chinese patients in the Shanghai area. METHODS: In 32 patients and 48 healthy controls, polymerase chain reaction amplified with sequence-specific primers (PCR-SSP) was performed to elucidate the relevance of certain alleles or polymorphic sequences of HLA-DRB1 with autoimmune hepatitis. RESULTS: The HLA-DRB1 typing by PCR-SSP showed that DR4 had a significantly increased frequency among patients with AIH versus that of healthy controls (46.9 vs 20.8%; relative risk = 3.35, P = 0.014). In the subtypes of DR4, there was a trend of an increase in the gene frequency of DRB1*0405 in patients with AIH versus that of healthy controls (21.9 vs 6.3%, P = 0.04, but corrected P (Pc) = 0.08). In addition, our analysis indicated a significant increase in the alleles frequency encoding Leu-Leu-Glu-Gln-Lys-Arg (LLEQRR) from the third hyperpolymorphic region (HVR3) of DR4 in the patients with AIH (86.7% of DR4 positive patients vs 40.0% in DR4 positive controls, P = 0.016, Pc = 0.028, relative risk (RR) = 9.75). CONCLUSION: Type I AIH among Chinese patients is associated with HLA-DR4. There is a relevance of type I AIH and LLEQRR sequence within the third hyperpolymorphic region of the DRB1 allele.     

Prevalence and epidemiology of autoimmune hepatitis

The incidence and characteristics of AIH differ in various geographic regions. Based on limited epidemiologic studies, the incidence of type 1 AIH among Caucasoid populations of Europe and North America ranges from 0.1 to 1.9/100,000/year. The disease is considerably less frequent in Japan. The relative proportion of AIH among cases with chronic hepatitis is low in regions with a high prevalence of viral hepatitis. Type 2 AIH is more frequent in southern Europe than in northern Europe, the United States, and Japan. The occurrence of anti-SLA/LP is also higher in European than in Japanese patients with type 1 AIH. The frequency of HLA markers that affect susceptibility to AIH varies between ethnic groups. DRB1*0301 (DR3) and DRB1*0401 (DR4) are the major risk factors for type 1 AIH in white European and North American populations. DRB1*0405 (DR4) is the principal risk factor in Japanese and adult Argentine patients with type 1 AIH, and DRB1*0404 (DR4) is the main susceptibility allele in Mestizo Mexicans. Children may have different clinical manifestations than adults, and the diagnoses of type 2 AIH, autoimmune sclerosing cholangitis, and APS1 should be considered. Uniform application of diagnostic criteria formulated by the International Autoimmune Hepatitis Group should strengthen future epidemiologic studies and extend awareness of AIH to yet unstudied minority groups.     

Autoimmune hepatitis from the paediatric perspective

Autoimmune hepatitis (AIH) is an important entity within the broad spectrum of autoimmune hepatobiliary disease comprised of AIH, primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Since the 1960s, AIH has been investigated with extensive clinical research aimed at effective therapeutic intervention. It was one of the first liver diseases where treatment was demonstrated to prolong survival. AIH occurs in children, as well as in adults. Its clinical manifestations in children may differ from classic adult AIH. These differences have elucidated certain aspects of AIH and hepatobiliary disease in general. There are two major patterns of AIH: type 1, with anti-smooth muscle antibodies and type 2, with anti-liver/kidney microsomal antibodies. The second type of AIH was first identified in children and is more common in younger patients. AIH often presents as acute disease in children and also in adults: the nomenclature has dropped the allusion to chronicity. Some children who have sclerosing cholangitis present with clinical disease closely resembling AIH; this AIH-like PSC, termed autoimmune sclerosing cholangitis (ASC), is also found in adults. Children with AIH may have identifiable monogenic disorders of immune regulation such as autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). Like adults with AIH, children with AIH usually respond very favourably to immunosuppressive treatment with corticosteroids ± azathioprine. True cures seem to be rare, although many children achieve a stable remission. Nonetheless children with AIH may develop cirrhosis and some require liver transplantation. Early diagnosis and improved treatment strategies may further improve the outlook for children with AIH.     

Autoimmune hepatitis/sclerosing cholangitis overlap syndrome in childhood: a 16-year prospective study

To investigate whether sclerosing cholangitis with an autoimmune serology characteristic of autoimmune hepatitis (AIH) and AIH are distinct entities, we studied 55 consecutive children with clinical and/or biochemical evidence of liver disease and circulating antinuclear (ANA), anti-smooth muscle (SMA), and/or liver-kidney-microsomal type 1 (LKM1) autoantibodies. They underwent liver biopsy, direct cholangiography, sigmoidoscopy, and rectal biopsy at presentation. Twenty-eight were diagnosed as AIH in the absence and 27 autoimmune sclerosing cholangitis (ASC) in the presence of radiological features of cholangiopathy. Twenty-six ASC and 20 AIH had ANA and/or SMA; 1 ASC and 8 AIH LKM1 autoantibody. Similarities between the 2 conditions included most clinical and biochemical parameters and a lower frequency of HLA DR4. Inflammatory bowel disease and histological biliary changes were more common in ASC; coagulopathy, hypoalbuminemia, lymphocytic periportal hepatitis, and HLA DR3 were more common in AIH. Histological biliary changes were observed in 65% of ASC and 31% of AIH patients. Eighty-nine percent responded to immunosuppression. Follow-up liver biopsies from 17 ASC and 18 AIH patients had similarly reduced inflammatory activity and no progression to cirrhosis. Sixteen follow-up cholangiograms from AIH patients and 9 from ASC patients were unchanged, while 8 ASC patients showed a progressive cholangiopathy. One child with AIH and ulcerative colitis developed sclerosing cholangitis 8 years after presentation. At 2 to 16 years (median, 7 years) from presentation, all patients are alive, including 4 ASC patients who underwent liver transplantation. In conclusion, ASC and AIH are similarly prevalent in childhood; cholangiography is often needed to distinguish between these 2 entities, which are likely to lie within the same disease process.     

Features and outcome of autoimmune hepatitis type 2 presenting with isolated positivity for anti-liver cytosol antibody.

BACKGROUND AND AIMS: Autoimmune hepatitis (AIH) type 2 is identified by the presence in the serum of anti-liver/kidney microsome type 1 autoantibody. Anti-liver cytosol autoantibody has been reported in children with autoimmune liver disorders mostly in association with anti-liver/kidney microsome reactivity. However, its role as a sole marker of AIH type 2 is debated. We describe here a series of 18 children and adolescents (15 girls, 3 boys) with AIH with serum anti-liver cytosol type 1 (aLC1) as the only autoimmune marker. METHODS: A retrospective review was conducted from 3 pediatric hepatology units of all children with an autoimmune liver disease associated with aLC1 as found by immunofluorescence and/or immunodiffusion or immunoblotting. RESULTS: Age at first symptoms ranged from 11 months to 14 years; 12 children presented with acute hepatitis, 1 with progressive jaundice, and 5 were asymptomatic. Anti-liver/kidney microsome, antimitochondria, and anti-actin autoantibodies were not detected. Signs of cirrhosis were present in 11 children. Immunosuppressive treatment was effective in all except 2 children who had subfulminant hepatic failure and who required liver transplantation. Sixteen patients (14 with their native liver) currently are alive; 14 patients still are on immunosuppressive therapy after 1 to 22 years. According to the international scoring system for the diagnosis of AIH, 16 patients corresponded to a definite diagnosis and 2 corresponded to a probable diagnosis. CONCLUSIONS: The presence of aLC1 in children with acute or chronic liver disease of unknown origin strongly supports a diagnosis of AIH and is an indication for early immunosuppressive therapy.     

Anti-mitochondrial antibody positive autoimmune hepatitis triggered by EBV infection in a young girl

Autoimmune hepatitis (AIH) is rare in children. Two types of childhood autoimmune hepatitis are recognized: AIH type 1 which is characterized by the presence of smooth muscle (SMA) and/or antinuclear (ANA) antibodies; and AIH type 2 which is positive for anti-liver kidney microsomal type 1 (anti-LKM-1) antibody. Anti-mitochondrial antibody (AMA) is considered the hallmark for primary biliary cirrhosis (PBC) that occurs primarily in adult women and is characterized by destruction of the intralobular bile ducts and progression to cirrhosis and liver failure. Antimitochondrial-antibody-positive AIH is extremely rare in children. We report a 13 year old Saudi girl with type-1 AIH who had a strongly positive anti-mitochondrial antibody and no evidence of small bile duct disease in the liver biopsy.     

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a hepatocellular inflammation that is characterised by a wide range of histopathologic (periportal interface hepatitis with plasma cell infiltration and piecemeal necrosis), biochemical (hypertransaminasemia, hypergammaglobulinaemia) and autoimmune (several autoantibodies presence) features. This relatively rare disorder frequently affects middle-aged women. There is no pathognomonic marker for AIH diagnosis, therefore it requires a careful rule out of other causes of liver disease together with the detection of a suggestive pattern of clinical and laboratory abnormalities. Scoring system for AIH diagnosis proposed by International Autoimmune Hepatitis Group has been used as a tool in clinical practice but is not sufficiently exclusive in terms of defining prognosis or treatment. AIH has been classified in two subtypes according to autoantibodies detected: 1 and 2, but this classification results in poor clinical implications. Previously known as subtype 3 is at the present included in subtype 1 because no clinical significant differences has been found between them. Aetiology, and molecular mechanisms still remain to be elucitaded in this disease, although viruses, drugs and molecular mimicry act presumably as a trigger in genetically predisposed patients (associated with HLA-DR3 and DR4 haplotypes). On the other hand, immunosuppressive therapy (corticosteroid or azathioprine) generally offers favourable response. Our aim is to review this disease from different points of view, considering: clinical, histopathological, etiologic, genetic, biochemical, autoimmune, treatment and prognosis features.     

Autoimmune hepatitis in children. Initial presentation as fulminant hepatic failure

There are few cases reported of autoimmune hepatitis (AIH) type 2 presenting as fulminant hepatic failure (FHF) in children. The purpose of this study was to report three girls with AIH type 2 that presented as FHF. METHODS: Over a period of 12 years, 123 patients with AIH diagnosed based on international criteria, 9 (7%) were type 2.3 of them presented as FHF. Other etiologies (viral, metabolic and toxic) were ruled out. The treatment was started with prednisone (2 mg-kg-day) and azathioprine (2 mg-kg-day). EVOLUTION: Patients 1 and 3 died while waiting for liver transplant (LT) at 72 and 48 hours after initiating medical treatment. Patient 2 underwent LT3 days after starting treatment, with excellent evolution at 3 years and 7 months of follow up. CONCLUSIONS: 1--AIH type 2 was very infrequent in our group. 2--33% of cases had initial presentation as FHF. 3--The course of the disease was aggressive, not responding to immunosuppressive therapy. The evolution was unfavorable in all patients. 4--LT is an alternative treatment for this severe disease.     

Autoantibodies and defined target autoantigens in autoimmune hepatitis: an overview

Autoimmune hepatitis (AIH) is a disease of unknown aetiology characterised by hypergammaglobulinaemia, non-organ and liver-related autoantibodies, association with HLA-DR3 or DR4 and a favourable response to immunosuppression. The current classification of AIH and the several autoantibodies/target autoantigens found in this disease are reported. The importance of these markers in the differential diagnosis and the study of pathogenesis of AIH is also given. AIH is subdivided into two major types: AIH type 1 (AIH-1) and AIH type 2 (AIH-2). AIH-1 is characterised by the detection of smooth muscle autoantibodies (SMA) and/or antinuclear antibodies (ANA). Antineutrophil cytoplasmic autoantibodies (ANCA), in most cases of perinuclear pattern (p-ANCA), by the indirect immunofluorescence assay, antibodies against the asialoglycoprotein receptor (anti-ASGP-R) and antibodies to soluble liver antigens or liver-pancreas (anti-SLA/LP) may be useful for the identification of individuals who are seronegative for ANA/SMA. AIH-2 is characterised 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). For these reasons, the distinction between AIH and chronic viral hepatitis is of particular importance. Cytochrome P450 2D6 (CYP2D6) is the major target autoantigen of anti-LKM-1 autoantibodies in both conditions (AIH-2 and HCV infection). Recent data have demonstrated the expression of CYP2D6 on the surface of hepatocytes, suggesting a pathogenetic role of anti-LKM-1 autoantibodies in liver injury. Family 1 of UDP-glycuronosyltransferases has been identified as the target autoantigen of anti-LKM-3. The molecular target of anti-SLA/LP autoantibodies has been identified recently as a 50 kDa protein with unknown structure and function. A liver-specific enzyme, the formiminotransferase cyclodeaminase, was identified as the target autoantigen of anti-LC1 autoantibodies. Anti-ASGP-R and anti-LC1 autoantibodies appear to correlate better with the severity of AIH and the response to treatment. The latter may suggest a pathogenic role of these autoantibodies in the hepatocellular damage in AIH. In general, however, autoantibodies should not be used to monitor treatment or to predict AIH activity or outcome. Finally, current knowledge concerning a specific form of AIH that may develop in some patients with a rare genetic syndrome, the autoimmune polyglandular syndrome type-1 (APS-1), is also discussed. Autoantibodies against liver microsomes (anti-LM) are the specific autoantibodies found in AIH as a disease component of APS-1. However, anti-LM autoantibodies have also been described in cases of dihydralazine-induced hepatitis. Cytochrome P450 1A2 has been identified as the target autoantigen of anti-LM autoantibodies in both disease entities.