Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q16637 (SMA)
 8,107 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concept of auto-immune hepatitis as a disease entity evolved from the descriptions of 'chronic active hepatitis' (CAH) in the 1950s. Several types of CAH are distinguished by disease-specific features. The distinctive (but not exclusive) markers for auto-immune CAH include: a negative test for HBsAg; female; Northern European ethnic background; multisystem disease expression; histological CAH with large areas of periportal piecemeal necrosis and plasmacytosis; pronounced hypergammaglobulinaemia; serum auto-antibodies the HLA B8-DR3 phenotype; responsiveness to corticosteroid therapy; and rarity of supervening hepatocellular carcinoma. Much weight is attached to the serological marker auto-antibodies to nuclear or smooth muscle (actin) antigens (ANA, SMA). However, these auto-antibodies do not have an absolute association with auto-immune CAH: the serological reactions are not yet standardized; titres decrease with remission of disease; and other auto-antibodies mark variant forms of auto-immune hepatitis. A more confident acceptance of auto-immune hepatitis as an entity requires detection of a liver-specific antigen, a valid experimental disease model in animals, and a better understanding of immune-mediated damage to liver cells.
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PMID:Auto-immune (lupoid) hepatitis: an entity in the spectrum of chronic active liver disease. 210 17

Chronic inflammatory liver diseases can be induced by virus infections, toxic-metabolic factors and/or autoimmune mechanisms. This overview deals with the immunopathogenesis of chronic hepatitis B and C and autoimmune hepatitis (AIH). 1. Chronic hepatitis B: The immune response to HBV-antigens is responsible both for viral clearance and disease pathogenesis during HBV-infection. The humoral immune response to HBsAg contributes to the clearance of circulating virus particles, the cell mediated immune response to HBsAg, HBcAg and polymerase antigen eliminates infected cells. The class I- and class II restricted T-cell-responses to HBV is strong, polyclonal and multispecific in acute HB with successful clearance of the virus, but weak or incomplete in chronic HB with viral persistence. In addition to ineffective immune response host and viral factors as well as abnormalities in virus-host interactions may be the main reasons for the maintenance of HBV-carrier status. 2. Chronic hepatitis C develop in more than 60% of infected patients. There is increasing evidence that the immune response to HCV-epitopes plays an important role in the course and the pathogenesis of the disease. It has been shown that CD4+ and CD8+ T-cells recognize viral peptides in the presence of class I and II molecules. The fine specificity and functional significance of liver infiltrating and peripheral blood T-cells demonstrate HCV specific immunodominant epitopes targeted by class Ii restricted CD4+ cells in patients with chronic HCV infection. The T-cell response correlates with disease activity. The cytokine release of T-cells resemble a TH1-like profile. Studies of the humoral immune response to HCV show a correlation between IgM-anti-HCV and disease activity. In vitro and in vivo anti-HCV secretion by PBMC is due to persistent antigenic stimulation of B-cells by ongoing production of viral antigens and reflects HCV replication in PBMC. Of special interest are several immune mediated disease and immune abnormalities in chronic hepatitis C. 3. Autoimmune hepatitis (AIH) is a distinct group of acute and chronic necro-inflammatory disorders of unknown etiology characterized by immunological and autoimmunological features including the presence of autoantibodies but without an antecedent of viral infections. Marker autoantibodies define 3 subtypes: Type I (ANA/SMA), Type II (LKM1-AB), Type II (SLA-AB). AIH is associated with a distinct genetic background (HLA A1, B8, DR3 or DR4). Several studies clearly demonstrate that liver cell damage in AIH is mediated by autoimmune reactions against normal constituents of hepatocytes. Although the precise mechanisms are not yet fully understood, there is now considerable evidence that autoantigens of the hepatocellular membrane in particular the ASGPR are important targets of liver damaging autoreactions in AIH. Cellular and humoral immune reactions against the human ASGPR correlate with disease activity and usually disappear under immunosuppressive therapy.
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PMID:[Immunopathology of chronic liver diseases]. 860 Jun 84

We present 10 Italian patients with type 2b autoimmune hepatitis (anti-LKMI positivity) and HCV infection. 6 patients had IgG concentrations above the upper limit of normal and all had histological features of chronic autoimmune hepatitis or chronic persistent hepatitis or cirrhosis. ANA and SMA were positive in 2 patients, pANCA in 3 patients. Anti-GOR were negative in all patients, 6 of them were HLA B8 DR3 and 2 HLA B8 DR4. Antibodies to HCV (tested by ELISA 2nd and 3rd generation) were positive in all patients and in 9 subjects were detected HCV RNA. The two patients with positivity for ANA and SMA were treated successfully with corticosteroids, but they relapsed after the drug withdrawal; the others received interferon, that had to be suspended in 2 patients because inducing an autoimmune thyroiditis. Although, at present, it is still not known if HCV is a really trigger factor in developing autoimmunity or if the two diseases are coincidental, the authors suggest that it is important for clinicians to use appropriate treatment strategies on the basis of the predominant illness.
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PMID:Type 2 autoimmune hepatitis and hepatitis C viraemia. 876 75

To determine the clinical, biochemical, and histological features, and outcome of childhood autoimmune hepatitis (AIH), we reviewed the medical records of 52 children with AIH, 32 (median age: 10 [2-15] years) anti-nuclear and/or smooth muscle antibody (ANA/SMA) positive, 20 (7 [0.8-14] years) liver/kidney microsomal antibody (LKM-1) positive, with median follow-up of 5 years (range 0.3-19). At presentation: 56% had symptoms of prolonged acute hepatitis; LKM-1 positive were younger (P = .011), with higher bilirubin (P = .007), and AST (P = .047); ANA/SMA positive had lower albumin (P = .023); 69% ANA/SMA positive, and 38% LKM-1 positive were cirrhotic (P = .080). ANA/SMA positive had increased frequency of HLA haplotype A1/B8/DR3/DR52a compared with controls (53% vs. 14%, P < .001). Of six (5 LKM-1 positive) with fulminant hepatitis, four were transplanted, one died, and one ANA/SMA positive improved with immunosuppression. Of 47 treated with immunosuppression, 2 (1 LKM-1 positive) died with no remission and 4 (2 LKM-1 positive) were transplanted 8 to 14 years after diagnosis. Immunosuppression was stopped successfully in 19% of ANA/SMA positive after a median of 3 years of treatment, but in none of LKM-1 positive. Baseline bilirubin and international normalized prothrombin ratio (INR) were independent variables predictive of outcome. In conclusion, ANA/SMA positive and LKM-1 positive AIH in childhood have clinical, biochemical, and histological differences, but similar severity and long-term outcome.
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PMID:Autoimmune hepatitis in childhood: a 20-year experience. 904 95

To determine the significance of antinuclear antibodies and their patterns of indirect immunofluorescence in type 1 autoimmune hepatitis, sera from 99 patients were evaluated. Patients with antinuclear antibodies had a lower frequency of liver transplantation (6% vs 22%, P = 0.04) than seronegative patients. They were also more commonly HLA-DR4-positive than seronegative patients (56% vs 30%, P = 0.05) and normal subjects (56% vs 30%, P = 0.004). The 42 patients with antinuclear antibodies and a diffuse pattern of indirect immunofluorescence had higher serum titers of ANA (serum titers > or = 1:500, 71% vs 14%, P < 0.0001) and SMA (serum titers > or = 1:500, 69% vs 27%, P = 0.003) than the 22 patients with antinuclear antibodies and a speckled pattern. These patients, however, were otherwise not distinguished by clinical features and treatment response. Patients with a speckled pattern had A1-B8-DR3 more frequently than patients with a diffuse pattern (65% vs 23%, P = 0.005) and normal subjects (65% vs 13%, P < 0.0001), but they had no other salient features. We conclude that patients with antinuclear antibodies have a better long-term prognosis than seronegative patients, and they have HLA-DR4 more commonly. The patterns of indirect immunofluorescence associated with ANA positivity have no practical clinical implications.
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PMID:Antinuclear antibodies and patterns of nuclear immunofluorescence in type 1 autoimmune hepatitis. 928 35

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.
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PMID:Autoimmune hepatitis/sclerosing cholangitis overlap syndrome in childhood: a 16-year prospective study. 1123 Jul 33

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.
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PMID:Autoimmune hepatitis. 1572 81