Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Hepatology ; 27(1): 254-63, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9425945

RESUMO

"Escape" variants of hepatitis B virus (HBV) can cause infection despite previous immunization. These viruses show alterations of the immunogenic major hydrophilic loop of the HBV small surface protein (s-protein). We studied whether HBV "escape" variants were selected in patients with graft infection after liver transplantation for HBV-related diseases who received passive immunoprophylaxis with high-dose polyclonal hepatitis B hyperimmune globulin (HBIG). For that, pre- and posttransplantation sera of 34 patients were analyzed for the occurence of HBV S-gene variants. In addition, binding of in vitro-translated variant s-proteins to HBIG was studied. Variants with exchanges of amino acid (aa) 144 (s144) in HBV genotype A and 145 in genotype D (s145) were found to emerge, persist, and predominate during HBIG, and thus fulfilled criteria of "escape" variants selected. In addition to already-known variants sG145R/K/E, we could demonstrate that newly described variants sX144G and sG145A were antigenically altered and showed impaired recognition by polyclonal HBIG in vitro. Diminished recognition of variant s-proteins correlated with the failure of HBIG to prevent infection of the liver graft with antigenically altered variant HBV Patients infected with "escape" variants s144 or s145 showed a worse clinical outcome compared with the other patients on high-dose, long-term HBIG prophylaxis (44% vs. 23% graft failure caused by HBV infection). Our results suggest that antigenically altered HBV variants s144 and s145 can be selected by HBIG and can influence clinical outcome after liver transplantation.


Assuntos
Variação Genética , Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Imunização Passiva , Transplante de Fígado , Adulto , Sequência de Aminoácidos , Sequência de Bases , Variação Genética/genética , Rejeição de Enxerto/virologia , Hepatite B/complicações , Hepatite B/prevenção & controle , Antígenos de Superfície da Hepatite B/imunologia , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Mutação , Cuidados Pós-Operatórios , Proteínas Virais/genética , Proteínas Virais/imunologia
2.
Hepatology ; 26(2): 478-84, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9252162

RESUMO

Hepatitis B virus (HBV) infection of the liver graft is a major complication after orthotopic liver transplantation (OLT) for HBV-related cirrhosis. A high viral load before OLT is a known risk factor, whereas the relevance of precore mutants of HBV is a subject of controversy. The aim of this study was to correlate the pretransplantation viral load and a pretransplantation infection with precore mutant HBV (pmHBV) or wildtype HBV (wtHBV) with allograft damage, graft failure, and survival after OLT. Sixty-nine patients with HBV cirrhosis underwent OLT under high dose immunoprophylaxis with anti-hepatitis B surface (HBs) hyperimmunoglobulins (HBIg). A pretransplantation infection with pmHBV and wtHBV was detected by polymerase chain reaction (PCR) and direct sequencing in 30 patients each (pmHBV and wtHBV group). Nine of 69 patients were PCR-negative (noHBV group). Median pretransplantation levels of HBV DNA assessed by hybridization assay were 42 pg/mL for pmHBV and 54 pg/mL for wtHBV patients. HBV recurred in 17 of 30 (57%) of pmHBV and in 14 of 30 (47%) of wtHBV patients and graft failure occurred in 6 of 30 (20%) of pmHBV and 7 of 30 (23%) of wtHBV patients. Neither HBV recurrence nor graft failure occurred in patients in whom no HBV DNA could be detected by PCR using primers flanking the HBV precore region (noHBV) patients. Allograft damage assessed by histology activity index (HAI) scoring was median 6 for pmHBV and 7 for wtHBV patients. Cumulative survival after 5 years was 72% for pmHBV, 74% for wtHBV, and 100% for noHBV patients. In this study, we provide evidence that pretransplantation viral load, but not infection with pmHBV, determines the outcome after OLT in patients on high dose HBIg prophylaxis.


Assuntos
Antígenos de Superfície da Hepatite B/imunologia , Hepatite B/complicações , Imunoglobulinas/imunologia , Transplante de Fígado , Adulto , DNA Viral/análise , Feminino , Hepatite B/prevenção & controle , Antígenos de Superfície da Hepatite B/análise , Humanos , Transplante de Fígado/efeitos adversos , Transplante de Fígado/mortalidade , Masculino , Pessoa de Meia-Idade , Recidiva
3.
Z Gastroenterol ; 35(6): 459-67, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9231990

RESUMO

The intercellular adhesion molecule 1 (ICAM-1, CD54) and the lymphocyte associated antigen 3 (LFA-3, CD58) have been found in soluble form (sCD54 and sCD58) in human sera. Data concerning their role in chronic liver disease and their usefulness in disease monitoring are contradictory. We addressed the question whether elevated sCD54/sCD58 correlated either with disease activity or with decreased elimination secondary to reduced liver function in chronic hepatitis B. We studied 31 patients with chronic hepatitis B undergoing interferon alpha therapy in a longitudinal fashion. Serum concentrations of sCD54 and sCD58 were measured at four weeks interval by specific Sandwich ELISA during a follow-up period of ten months. The maximal difference in concentration of each biochemical parameter, e.g., delta AST, delta gGt, delta bilirubin, was determined for each patient during the whole follow-up period. These differences were correlated with the variation in sCD54 (delta sCD54) and sCD58 (delta sCD58) at the respective time points. Using this method, we were able to eliminate interindividual differences in serum concentrations for sCD54 and sCD58 and to avoid bias due to preselection of patients. We found that delta sCD54 correlated with delta AST (p = 0.001) and delta ALT (p = 0.002), whereas there was no such correlation for delta sCD58. Interferon therapy did not affect sCD54 or sCD58 levels. Neither hepatitis B viremia nor the immune response to hepatitis B during the time of seroconversion to anti-HBe did significantly increase sCD54 or sCD58 levels. However, delta sCD54 was associated with delta gamma GT (p = 0.005) and delta sCD58 correlated with delta bilirubin (p = 0.037); a negative correlation was found for delta sCD54 with delta cholinesterase (p = 0.007). Our findings imply that sCD54 and sCD58 may be associated with a decrease in liver function that accompanies hepatic disease activity. sCD54 and sCD58 did not prove useful to monitor disease activity or response to interferon therapy in chronic hepatitis B. From our data we conclude, that decreased elimination of soluble adhesion molecules sCD54 and sCD58 in advanced liver disease may be responsible for increased serum concentrations detected.


Assuntos
Antígenos CD58/sangue , Hepatite B/terapia , Molécula 1 de Adesão Intercelular/sangue , Interferon-alfa/uso terapêutico , Adulto , Idoso , Feminino , Hepatite B/imunologia , Anticorpos Anti-Hepatite B/sangue , Hepatite Crônica/imunologia , Hepatite Crônica/terapia , Humanos , Testes de Função Hepática , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade
4.
Arch Virol ; 141(11): 2091-101, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8973525

RESUMO

In most patients with chronic hepatitis B positive for antibodies (anti-HBe) to HBe antigen (HBeAg), a pre-core mutant hepatitis B virus (HBV) with a point-mutation at nt. 1896 can be isolated. Clinical significance of the mutant virus in chronic hepatitis B is not proven yet, and screening of large numbers of sera during different clinical courses of numerous patients is necessary. We therefore aimed to develop a fast and reliable assay, that allows to discriminate wildtype from nt. 1896 G-->A mutant HBV and to determine the ratio of mutant and wildtype HBV in patients' sera. A mutation specific polymerase chain reaction (ms PCR) with new primers served to distinguish nt. 1896 G-->A mutant from wildtype HBV. This msPCR proved to be more sensitive and specific than similar assays described previously. When compared to a dilution series of a cloned HBV-DNA standard, the amount of wildtype and nt. 1896 G-->A mutant HBV could be determined semiquantitatively. 10(2) to 10(7) copies of each HBV-DNA (equivalent to 10(5) to 10(10) copies of HBV-DNA/ml patients' serum) could be amplified with steadily increasing signals. MsPCR proved to be specific as 10(7) copies did not give an amplification signal if they did not match the respective primer pair used. In a mixed population of mutant and wildtype virus, msPCR allows to detect even a low amount of the minor HBV strain (0.1-0.01%, of the viral population) and to determine the ratio of wildtype and mutant HBV. MsPCR is as fast and convenient to perform as an unmodified PCR. It requires careful performance to avoid contamination but no specific equipment. Clinical usefulness of msPCR was demonstrated when the ratio of wildtype to mutant HBV was determined in 86 sera collected during 3 to 7.5 years follow up of 9 patients suffering from anti-HBe positive chronic hepatitis B. We conclude that this assay conveniently allows to study patients with chronic hepatitis B in order to detect and follow-up the emergence of pre-core stop-codon mutant HBV in correlation to the clinical course.


Assuntos
Códon de Terminação/genética , Vírus da Hepatite B/genética , Hepatite B/virologia , Mutação Puntual , Reação em Cadeia da Polimerase/métodos , Doença Crônica , Estudos de Avaliação como Assunto , Seguimentos , Antígenos E da Hepatite B/genética , Humanos , Sensibilidade e Especificidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA