UMLS:C0019158 - FACTA Search

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Query: UMLS:C0019158 (hepatitis)
30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Homozygosity for alpha 1-antitrypsin deficiency, usually of the genotype PIZZ, is one of the more common single gene defects in infants of European origin, occurring in about 1 in 2000 to 1 in 7000 of the newborn population. About 17% of such infants present with neonatal hepatitis and a small number with intracranial haemorrhage thought to be caused by vitamin K deficiency associated with cholestasis. At least 3% of PIZZ infants will die of cirrhosis in later childhood unless successfully treated by liver transplant. The pathogenesis of the liver disease is not understood and this is unsatisfactory both for treatment and for genetic counselling. The locus coding for alpha 1-antitrypsin (alpha 1AT) is designated PI for proteinase inhibitor. Careful study of the genotypes at this locus in neonatal disease shows that the only certain association is with the homozygous PIZZ genotype. The mutation results in a normal rate of synthesis of a polypeptide that becomes entrapped in the endoplasmic reticulum of the hepatocyte. Some other factor (or factors), as yet unidentified, determines whether severe liver damage results. The low level of alpha 1AT in the plasma seems unlikely to be the primary cause of damage but may play a secondary role. There is some evidence that the other factor(s) may be familial since in one study, though not in all, a high correlation for severity of liver disease was found between PIZZ siblings. The heterogeneity of the clinical course does not result from heterogeneity of PIZ alleles and there is no evidence that it is determined by variation in other related genes on chromosome 14. Only two possible clues have emerged so far. There is some evidence of a protective effect of breast-feeding, and a recent study has found the HLA class II DR3 antigen to be more common than expected in children with alpha 1-antitrypsin deficiency and liver disease. Accumulation of alpha 1AT protein in the hepatocytes may predispose them to some unidentified alteration of the immune response. It is possible that lack of antiprotease activity in the plasma might exacerbate the original damage, so the possibility of useful therapy with alpha 1AT cannot be ruled out entirely. At present, there is no valid way of predicting the severity of disease in a PIZZ child; hence, it is common for parents of a severely affected child to wish to terminate any future PIZZ pregnancy. The most direct method to diagnose the PIZZ genotype of a chorion villus sample is by allele-specific hybridization or sequencing of amplified DNA.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Genetics of alpha 1-antitrypsin deficiency in relation to neonatal liver disease. 218 61

Studies on the quantitative expression of the Major Histocompatibility Complex (MCH) in hepatocytes chronically infected by Hepatitis B Virus (HBV) report that an increased expression of these antigens could be related to a good immunological response. In the present work we analyze the expression of the MCH antigens in cryostatic sections of liver biopsies taken from subjects (19 children) with various forms of HBsAg positive chronic hepatitis. A high expression of HLA class I antigens and a high degree of hepatocyte necrosis was evident in Chronic Active Hepatitis (CAH) and Chronic Lobular Hepatitis (CLH). On the contrary, subjects with histological diagnosis of Chronic Persistent Hepatitis (CPH) showed a low expression of such antigens. There was however, the difference that in subjects with high hepatic cytolysis and high expression of HLA class I antigens, serum HBV-DNA was clearly present in almost all the cases with CAH, but not detectable in all cases with CLH. The expression of HLA class II antigens and of Beta2 microglobulin was the same in all 19 cases. All cases with HBV-DNA positivity with high class I antigen expression had active hepatitis which seems to suggest that all attempts at viral clearance on the part of the immune system have been in vain. We hope our paper will be an additional parameter for evaluating the course of hepatitis during Interferon treatment.
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PMID:Different expression of HLA class I antigens in liver of children with chronic hepatitis B, evaluated by immunohistochemical method. 269 19

Primary biliary cirrhosis (PBC) is characterized by lymphoid infiltrates in the portal tracts of the liver and the occurrence of antimitochondrial autoantibodies in serum directed against components of the pyruvate dehydrogenase complex and the other alpha-keto acid dehydrogenase complexes. These enzymes are located on the inner mitochondrial membrane. The destruction of the biliary tract in PBC is thought to be mediated by autoreactive liver-infiltrating T cells exerting cytotoxic activity or releasing certain lymphokines. In this study the reactivity of liver infiltrating T cells was shown to a bovine pyruvate dehydrogenase complex (PDH), a purified E2 subunit (PDH-E2) and a crude preparation of human liver mitoplasts (HLM), i.e. mitochondria depleted of their outer membranes. Peripheral blood lymphocytes (PBL) from 11 of 15 patients (73.3%) with PBC showed a HLA class II-restricted proliferative response to the PDH complex whereas PBL from patients with chronic viral hepatitis, autoimmune hepatitis or extrahepatic cholestatic icterus (n = 20) and healthy controls (n = 5) did not. In addition 13 of 15 PBL from patients with PBC (86.6%) and three of nine PBL from patients with autoimmune hepatitis (33.3%) reacted with the crude HLM preparation whereas no reactivity was found with PBL from eight patients with chronic viral hepatitis, three patients with extrahepatic cholestasis or five healthy controls. Clonal analysis of 115 liver-infiltrating T cells derived from two diagnostic liver biopsies of patients with PBC revealed a predominance of activated CD4+CD8- T helper cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autoreactive liver-infiltrating T cells in primary biliary cirrhosis recognize inner mitochondrial epitopes and the pyruvate dehydrogenase complex. 769 99

The frequencies of HLA B54, DR4, DR53 and DQ4 were significantly higher in patients with autoimmune hepatitis than in healthy controls. HLA-DR4 was most frequently associated with autoimmune hepatitis. To define the HLA class II gene which has the susceptibility or resistance to autoimmune hepatitis, we performed HLA class II genotyping using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method. The frequency of DRB1*0405 was significantly higher in autoimmune hepatitis than in controls. However, there was no significant difference in the frequency of the DR4 associated Dw-allele between the patients and the controls who were DR4-positive. Six DR4-negative patients had DR2, but there was no significant difference in the frequency of the DR2-associated Dw-alleles compared with the DR2-positive controls. Comparison of the amino acid residues of DRB1 chain suggested that the basic amino acid at position 13, which is present only on the DR2 and DR4 B1 molecules (Arg on DR2 and His on DR4), contributes to the susceptibility to autoimmune hepatitis among Japanese.
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PMID:[Molecular biological analysis of HLA class II gene in autoimmune hepatitis among Japanese]. 809 52

The genetic background of autoimmune diseases becomes more and more evident. Immunogenetics comprises the analysis of genes and their products located at the region 6p21 on the short arm of chromosome 6, which is also known as the major histocompatibility complex (MHC). MHC class I and II genes are highly polymorphic. The complement genes C2, C4A, C4B, and BF, which are also polymorphic, became known as MHC class III genes. In autoimmune hepatitis type 1, there is a dual association for white persons with either HLA-A1-B8-DR3 or HLA-DR4. In patients from Japan, autoimmune hepatitis type 1 is predominantly associated with HLA-DR4. This dual association is confirmed at the DNA level. Whereas only limited data are available for autoimmune hepatitis type 2, the association of primary biliary cirrhosis with HLA-DR8 is based on several studies. Primary sclerosing cholangitis is associated with HLA-B8-DR3 and -DR52a. This association was confirmed at the DNA level because of a significant increase of the DRB3*0101 allele. For DRB3*0101-negative individuals, a second association with DRB5*0101 (= DR2) was described. Further analysis of the hypervariable region of the HLA class II molecule indicates that lysine at position 71 is crucial for autoimmune hepatitis type 1 in white persons, whereas position 13 is important for people from Japan. In contrast, leucine at position 35 is important for patients with primary biliary cirrhosis, whereas leucine at position 38 is an important risk factor for primary sclerosing cholangitis. The MHC class III allele C4A-QO is significantly increased in autoimmune hepatitis type 1 and 2 and in primary biliary cirrhosis. Advances in immunogenetics will certainly increase our knowledge of the etiology and pathogenesis of immune-mediated liver diseases, which hopefully will lead to more specific therapeutic interventions.
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PMID:Immunogenetics of chronic liver diseases. 819 17

In hepatitis C, both susceptibility to infection and the course of disease may depend on differences in the immune response. As the major histocompatibility complex (MHC) plays a crucial role in antigen presentation, we investigated a possible relationship between susceptibility to hepatitis C virus (HCV) infection and human leucocyte antigen (HLA) alleles. Therefore, phenotype frequencies of HLA were compared in 186 anti-HCV positive patients with end-stage renal disease (ESRD) to 328 anti-HCV negative patients with ESRD. HLA class I alleles were determined serologically and HLA class II alleles (DRB1, DQA1, DQB1) by the polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) technique. Additionally, in anti-HCV positive patients we looked for a relationship between the activity of hepatitis C (indicated by elevation of transaminases or the presence of viremia) and HLA determinants. For the three criteria (antibody status, elevation of transaminases and viremia) a significant association to HLA alleles was not found in patients with ESRD. This suggests that neither susceptibility to HCV infection nor the biochemical activity of hepatitis and HCV-RNA positivity seem to be strongly related to HLA status in Caucasian patients with end-stage renal disease.
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PMID:No significant influence of HLA determinants on susceptibility to hepatitis C virus infection in Caucasian patients with end-stage renal disease. 902 18

Interferon-alpha therapy is effective in only approximately 20% of individuals with chronic HCV infection. A knowledge of the genetic and/or environmental factors that underlie this heterogeneity of response should provide useful predictors of clinical outcome. HCV infected patients and healthy subjects were selected from the expatriate Egyptian population living in Qatar, where chronic HCV infection poses a serious health problem. HCV infection was confirmed by ELISA and RT-PCR. Fifty five patients received interferon-alpha therapy for 6 months and their response was assessed by liver enzyme activity and histology of liver biopsies; the patient responses were followed during treatment and for 1 year afterwards. Twenty five patients were characterised as responders, and the remaining 30 as non-responders. All individuals in the study were typed for HLA class II alleles. Data were analysed by univariate and multivariate statistical methods. Expression of the HLA DR2 Major Histocompatibility class II allele is significantly associated with a beneficial response to interferon-alpha therapy in Egyptian patients (p < 0.005). This association is independent of cirrhosis, the absence of which also showed a significant association with response to therapy (p < 0.005). Our results therefore provide evidence that HLA DR2 is an important additional factor for predicting a long term response to interferon-alpha therapy in chronic HCV hepatitis.
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PMID:Interferon-alpha therapy in HCV hepatitis: HLA phenotype and cirrhosis are independent predictors of clinical outcome. 956 99

Both direct viral cytopathic effects and host immune responses appear to be important in the pathogenesis of hepatitis C virus (HCV) infection. Liver transplantation provides a means to explore the role of the immune system in the development of HCV-related liver damage through comparing the natural history of HCV in patients with different degrees of donor-recipient human leukocyte antigen (HLA) matching. We evaluated 36 patients with recurrent hepatitis C viremia following liver transplantation to determine whether hepatocellular injury or progression to bridging fibrosis occur more rapidly when donor and recipients share HLA alleles. HLA typing for the HLA-A and HLA-B loci was performed by serological techniques and PCR-based oligotyping was used to type alleles of the DRB1, DRB3, DQA1, and DQB1 loci. A median of eight liver biopsies, obtained during a median follow-up of 36 months, were reviewed per patient. Donor-recipient sharing of alleles of HLA-DQB1 or DRB1 was associated with more rapid development of recurrent hepatitis by univariate analysis (chi2=5.7, P=0.02 and chi2=5.54, P=0.02 respectively). However, only sharing of HLA-DRB1 alleles was identified as an independent predictor of reduced time to recurrent histologic injury by multivariate analysis (chi2 =5.74, P=0.02). Furthermore, sharing of HLA-DRB3 and histologic evidence of rejection were associated with more rapid progression to bridging fibrosis both by univariate methods (chi2=4.12, P=0.04 and chi2=4.66, P=0.03 respectively), and by multivariate analysis (chi2=13.01, P=0.001). These findings suggest that HLA class II-restricted immune responses may contribute to the pathogenesis of HCV-related liver injury in liver transplant recipients.
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PMID:Donor-recipient sharing of HLA class II alleles predicts earlier recurrence and accelerated progression of hepatitis C following liver transplantation. 986 33

Fulminant and severe viral hepatitis are frequently associated with mutant hepatitis B virus (HBV) strains. In this study, the genetic background of a viral strain causing severe subfulminant outcome in heart-transplanted patients was studied and compared with viral hepatitis B strains that were not linked to severe liver disease in the same setting. A total of 46 patients infected nosocomially with HBV genotype A were studied. Five different viral strains were detected, infecting 3, 9, 5, 24, and 5 patients, respectively. Only one viral strain was found to be associated with the subfulminant outcome and 3 patient deaths as a consequence of severe liver disease. The remaining 43 patients with posttransplantation HBV infection did not show this fatal outcome. Instead, symptoms of hepatitis were generally mild or clinically undiagnosed. Comparison of this virus genome with the four other strains showed an accumulation of mutations in the basic core promoter, a region that influences viral replication, but also in hepatitis B X protein (HBX) (7 mutant motifs), core (10 mutant motifs), the preS1 region (5 mutant motifs), and the HBpolymerase open reading frame (17 motifs). Some of these variations, such as those in the core region, were located on the tip of the protruding spike of the viral capsid (codons 60 to 90), also known in part as an important HLA class II-restricted epitope region. These mutations might therefore influence the immune-mediated response. The viral strain causing subfulminant hepatitis was, in addition, the only strain with a preCore stop codon mutation and, thus, hepatitis B e antigen (HBeAg) expression was never observed. The combination of these specific viral factors is thought to be responsible for the fatal outcome in these immune-suppressed heart-transplant recipients.
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PMID:Three cases of severe subfulminant hepatitis in heart-transplanted patients after nosocomial transmission of a mutant hepatitis B virus. 1034 33

The HLA class II-restricted T-cell response to hepatitis C virus (HCV) antigens is believed to influence the final outcome of hepatitis C, because it is vigorous in patients who recover from acute hepatitis C, but it is weak in those who develop a chronic infection. For this reason, exogenous stimulation of T-cell responses in chronic HCV infection may represent a strategy to cure patients with chronic hepatitis C by approximating the vigor of their T-cell reactivity to that of patients who succeed in recovering from hepatitis. It may also be a preventive approach to avoid spread of the virus by facilitating the development of a vigorous protective response at the very early stages of infection. T-cell-based vaccines composed of immunodominant, promiscuous, and conserved T-cell epitopes may represent a powerful tool to achieve optimal stimulation of the T-cell reactivity. To identify HLA class II-restricted T-cell epitopes useful for this purpose, 22 subjects with acute HCV infection were studied and followed for an average time of 29 months. Eight of them recovered from hepatitis, and 14 developed a chronic infection. Overlapping 20-mer peptides covering the entire core and NS4 antigens and a panel of peptides representing highly conserved regions of core, NS3, NS4, and NS5 were used. By direct peripheral blood T-cell stimulation and by fine-specificity analysis of HCV-specific T-cell lines and clones, highly immunogenic T-cell epitopes were identified within core, NS3, and NS4. All these epitopes are immunodominant and highly conserved among the known HCV isolates. Moreover, they are promiscuous, because they can be presented to T cells by different HLA class II molecules. Immunodominance, sequence conservation, and promiscuity make these epitopes ideal components of preventive or therapeutic T-cell-based vaccines against HCV.
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PMID:Conserved hepatitis C virus sequences are highly immunogenic for CD4(+) T cells: implications for vaccine development. 1049 64

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