Anticorpos contra os antígenos não estrutural c100/3 e estrutural core do vírus da hepatite C (HCV) em pacientes de hemodiálise

Two groups of patients undergoing hemodialysis (HD) maintenance were evaluated for their antibody response to non-structural c100/3 protein and structural core protein of hepatitis C virus (HCV). Forty-six patients (Group 1) never presented liver abnormalities during HD treatment, while 52 patients (Group 2) had either current or prior liver enzyme elevations. Prevalence rates of 32.6% and 41.3% were found for anti-c100/3 and anti-HCV core antibodies, respectively, in patients with silent infections (Group 1). The rate of anti-c100/3 in patients of Group 2 was 71.15% and reached 86.5% for anti-HCV core antibodies. The recognition of anti-c100/3 and anti-core antibodies was significantly higher in Group 2 than in Group 1. A line immunoassay composed of structural and non-structural peptides was used as a confirmation assay. HBV infection, measured by the presence of anti-HBc antibodies, was observed in 39.8% of the patients. Six were HBsAg chronic carriers and 13 had naturally acquired anti-HBs antibodies. The duration of HD treatment was correlated with anti-HCV positivity. A high prevalence of 96.7% (Group 2) was found in patients who underwent more than 5 years of treatment. Our results suggest that anti-HCV core ELISA is more accurate for detecting HCV infection than anti-c100/3. Although the risk associated with the duration of HD treatment and blood transfusion was high, additional factors such as a significant non-transfusional spread of HCV seems to play a role as well. The identification of infective patients by more sensitive methods for HCV genome detection should help to control the transmission of HCV in the unit under study.Dois grupos de pacientes em tratamento hemodialítico foram avaliados quanto às respostas de anticorpos contra as proteínas não estrutural c100/3 (anti-c100/3) e estrutural core (anti-HCV core) do vírus da hepatite C (HCV). Quarenta e seis pacientes (Grupo 1) nunca apresentaram alterações dos níveis de alanina aminotransferase (ALT) durante o tratamento hemodialítico, ao passo que 52 pacientes (Grupo 2) têm ou já tiveram elevações desta enzima hepática. Em pacientes sem alterações bioquímicas evidentes (Grupo 1) foram encontradas prevalências de 32.6% e 41.3% para anti-c100/3 e anti-HCV core, respectivamente. No Grupo 2, estas prevalências foram de 71,15% e 86,5%. Um teste composto de peptídeos estruturais e não estruturais imobilizados separadamente e dispostos em bandas paralelas em fitas de nailon, foi usado como teste confirmatório. A infecção pelo HBV, avaliada pela presença de anticorpos anti-HBc foi observada em 39.8% dos pacientes; 6 eram portadores crônicos de HBsAg e 13 possuiam anti-HBs adquiridos naturalmente. O tempo de tratamento hemodialítico teve correlação com a positividade para anti-HCV. A prevalência de 96,7% (Grupo 2) foi encontrada em pacientes que tiveram mais de 5 anos de tratamento. Nossos resultados sugerem que o anti-HCV core é um marcador mais preciso para detectar a infecção pelo HCV do que o anti-c100/3. Apesar dos riscos associados com a duração do tratamento e transfusões sanguíneas, uma significante disseminação não transfusional do HCV parece ocorrer dentro da unidade. A identificação de pacientes infectantes por métodos sensíveis como a detecção do genoma viral deverá auxiliar no controle da transmissão do HCV na unidade em estudo

Distribution of HCV genotypes among different exposure categories in Brazil

Hepatitis C virus (HCV) infection is widespread and responsible for more than 60% of chronic hepatitis cases. HCV presents a genetic variability which has led to viral classification into at least 6 genotypes and a series of subtypes. These variants present characteristic geographical distribution, but their association with different responses to treatment with interferon and severity of disease still remains controversial. The aim of this study was to investigate the patterns of distribution of HCV genotypes among different exposure categories in Brazil. Two hundred and fifty anti-HCV positive samples were submitted to HCV-RNA detection by RT-PCR and their genotype was determined by restriction fragment length polymorphism (RFLP) analysis. In addition, the genotype/subtype of 60 samples was also determined by a reverse hybridization assay. HCV 1 was the most prevalent (72.0%), followed by type 3 (25.3%), HCV 2 (2.0%) and HCV 4 (0.7%). The HCV genotype distribution varied among the different exposure categories, with HCV 1 being more frequent among blood donors, hemophiliacs and hemodialysis patients. A high frequency of HCV 3 was observed in cirrhotic patients, blood donors from the South of Brazil and injecting drug users (IDUs). The general distribution of the HCV genotype in Brazil is similar to that in other regions of the world

Genotyping hepatitis C virus from hemodialysis patients in Central Brazil by line probe assay and sequence analysis

The present study examined the distribution of hepatitis C virus (HCV) genotypes and subtypes in a hemodialysis population in Goiás State, Central Brazil, and evaluated the efficiency of two genotyping methods: line probe assay (LiPA) based on the 5' noncoding region and nucleotide sequencing of the nonstructural 5B (NS5B) region of the genome. A total of 1095 sera were tested for HCV RNA by RT-nested PCR of the 5' noncoding region. The LiPA assay was able to genotype all 131 HCV RNA-positive samples. Genotypes 1 (92.4%) and 3 (7.6%) were found. Subtype 1a (65.7%) was the most prevalent, followed by subtypes 1b (26.7%) and 3a (7.6%). Direct nucleotide sequencing of 340 bp from the NS5B region was performed in 106 samples. The phylogenetic tree showed that 98 sequences (92.4%) were classified as genotype 1, subtypes 1a (72.6%) and 1b (19.8%), and 8 sequences (7.6%) as subtype 3a. The two genotyping methods gave concordant results within HCV genotypes and subtypes in 100 and 96.2% of cases, respectively. Only four samples presented discrepant results, with LiPA not distinguishing subtypes 1a and 1b. Therefore, HCV genotype 1 (subtype 1a) is predominant in hemodialysis patients in Central Brazil. By using sequence analysis of the NS5B region as a reference standard method for HCV genotyping, we found that LiPA was efficient at the genotype level, although some discrepant results were observed at the subtype level (sensitivity of 96.1% for subtype 1a and 95.2% for subtype 1b). Thus, analysis of the NS5B region permitted better discrimination between HCV subtypes, as required in epidemiological investigations

Detection of hepatitis C virus RNA by in situ hybridization in paraformaldehyde fixed biopsies

Fourteen hepatitis C virus (HCV) chronically infected patients were submitted to routine liver biopsy for histological evaluation. Liver samples were assayed to HCV-RNA by in situ hybridization, using digoxigenin labeled probe. HCV genotypes were found to be predominantly type 1 (71.4%), followed by genotype 3 (21.4%), and genotype 2 (7.2%). Alanine-aminotransferase levels were raised in 10 patients. The histopathological scores were minimal (21.4%), mild (57.2%), and moderate (21.4%). Viral RNA was detected in liver cells from nine patients (64.3%). ISH method provides localization and poor confirmation of HCV RNA in the liver tissue of HCV chronic patients

Immunization aganist hepatitis B in children from endemic zone: evaluation of the antibody response against the DNA recombinant vaccine (Engerix B-20 mcg)

A previous seroepidemiological study in the rural zone of Vargem Alta (ES) SouthEast of Brazil, showed a prevalence of up to 9% of hepatitis B surface antigen (HBsAg) in some areas. One hundred susceptible children aging 1 to 5 years old were selected and immunized with a recombinant DNA hepatitis B vaccine (Smith-Kline 20 mcg) using the 0-1-6 months vaccination schedule. Blood samples were collected at the time of the first vaccine dose (month 0) in order to confirm susceptible individuals and 1,3,6 and 8 months after the first dose , to evaluate the antibody response. Our results showed that two and five months after the second dose, 79% and 88% of children seroconverted respectively, reaching 97% after the third dose. The levels of anti-HBs were calculated in milli International Units/ml (mIU/ml) and demonstrated the markedly increase of protective levels of antibodies after the third dose. These data showed a good immunogenicity of the DNA recombinant hepatitis B vaccine when administered in children of endemic areas

Imunização contra Hepatite B em crianças de zona endêmica: avaliação da resposta de anticorpo à vacina HB recombinante (Engerix B-20mcg)

A previous seroepidemiological study in the rural zone of Vargem Alta (ES) SouthEast of Brazil, showed a prevalence of up to 9% of hepatitis B surface antigen (HBsAg) in some areas. One hundred susceptible children aging 1 to 5 years old were selected and immunized with a recombinant DNA hepatitis B vaccine (Smith-Kline 20 mcg) using the 0-1-6 months vaccination schedule. Blood samples were collected at the time of the first vaccine dose (month 0) in order to confirm susceptible individuals and 1,3,6 and 8 months after the first dose , to evaluate the antibody response. Our results showed that two and five months after the second dose, 79% and 88% of children seroconverted respectively, reaching 97% after the third dose. The levels of anti-HBs were calculated in milli International Units/ml (mIU/ml) and demonstrated the markedly increase of protective levels of antibodies after the third dose. These data showed a good immunogenicity of the DNA recombinant hepatitis B vaccine when administered in children of endemic areas.Um estudo soroepidemiológico prévio na zona rural de Vargem Alta (ES) - Sudeste do Brasil, mostrou uma predominância de até 9% do antígeno de superfície da Hepatite B (HBsAg). Foram selecionadas 100 crianças com faixa etária entre 1 e 5 anos de idade, as quais foram imunizadas com vacina contra Hepatite B -DNA recombinante (Smith-Kline,20 mcg) nos meses 0,1 e 6. Foram coletadas amostras de sangue antes da primeira dose da vacina (mês 0) para confirmação dos susceptíveis, e nos meses 1,3,6 e 8 após a vacinação para avaliação da resposta vacinai. Os resultados mostraram que 79 e 88% das crianças apresentaram soroconversão dois e cinco meses após a segunda dose respectivamente, atingindo 97% de soroconversão, após a 3a.dose. Os níveis de anti-HBs foram calculados em miliunidades internacionais/ml (mUI/ml), demonstrando um considerável aumento dos níveis de anticorpos protetores após a 3a. dose. Os resultados demonstraram uma boa imunogenicidade da vacina de DNA recombinante contra hepatite B, quando administradas em crianças de áreas endêmicas