RESUMO
BackgroundThe hepatitis C virus has been recognized as the leading cause of chronic liver disease in the world. Host genetic factors have been implicated in the persistence of hepatitis C virus infection. Single nucleotide polymorphisms at positions -607 C/A (rs1946518) and -137 G/C (rs187238) in the IL-18 gene promoter have been suggested to be associated with delayed hepatitis C virus clearance and persistence of the disease.ObjectiveIdentify these polymorphisms in a population infected with hepatitis C virus from the Brazilian Amazon region.MethodsIn a cross-sectional analytical study conducted in Belém, Pará, Brazil, 304 patients infected with hepatitis C virus were divided into two groups: group A, patients with persistent infection; group B, patients with spontaneous clearance. The control group consisted of 376 volunteers not infected with hepatitis C virus. Samples were analyzed by RT-PCR for the detection of viral RNA and by RFLP-PCR to evaluate the presence of the -137 G/C and -607 C/A IL-18 gene promoter polymorphisms.ResultsComparison of polymorphism allele frequencies between the patient and control groups showed a higher frequency of allele C at position -607 among patients (P=0.02). When the association between the polymorphisms and viral infection was analyzed, patients carrying genotype C/A at position -607 were found to be at higher risk of persistent hepatitis C virus infection (P=0.03).ConclusionThe present results suggest a possible role of the -607 IL-18 gene promoter polymorphism in the pathogenesis of hepatitis C virus infection.
ContextoO vírus da hepatite C é reconhecido como a maior causa de doença hepática crônica no mundo. Fatores genéticos do hospedeiro têm sido implicados na persistência da infecção pelo vírus da hepatite C. Polimorfismos de nucleotídeos únicos na posição -607 C/A (rs1946518) e -137 G/C (rs187238) na região promotora do gene da IL-18 têm sido evidenciados em alguns estudos que sugerem sua associação ao atraso na depuração do vírus da hepatite C e na persistência da doença.ObjetivoO presente estudo pretende identificar esses polimorfismos em uma população da região da Amazônia Brasileira infectada pelo vírus da hepatite C.MétodosEstudo do tipo transversal analítico no município de Belém-PA foi realizado em 304 pacientes infectados pelo vírus da hepatite C, divididos em: grupo A, pacientes com infecção persistente; grupo B, pacientes que apresentaram clareamento viral. Como grupo controle participaram 376 voluntários não infectados pelo vírus da hepatite C. As amostras foram submetidas à RT-PCR, para detecção do RNA viral e, posteriormente, à RFLP-PCR para avaliação do polimorfismo na região promotora do gene da IL-18, nas posições -137 G/C e -607 C/A.ResultadosA comparação das frequências dos polimorfismos no grupo de pacientes com o grupo controle demonstrou uma maior frequência do alelo C na posição -607 entre os pacientes (P=0,02) que no grupo controle. Na análise da associação dos polimorfismos com a infecção viral foi obtido que portadores do genótipo C/A na posição -607 possuíam maior risco de infecção persistente pelo vírus da hepatite C (P=0,03).ConclusãoNossos resultados sugerem uma possível implicação do polimorfismo da região promotora -607 do gene IL-18 na patogenia da infecção pelo vírus da hepatite C.
Assuntos
Feminino , Humanos , Masculino , Hepatite C/genética , /genética , Polimorfismo de Nucleotídeo Único , Brasil , Estudos Transversais , DNA Viral/análise , Predisposição Genética para Doença , Genótipo , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Regiões Promotoras Genéticas/genética , RNA ViralRESUMO
Introduction In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil. Methods Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed. Results Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher ...
Assuntos
Adulto , Feminino , Humanos , Masculino , Portador Sadio/virologia , DNA Viral/análise , Vírus da Hepatite B/genética , Hepatite B Crônica/virologia , Mutação , Regiões Promotoras Genéticas/genética , Sequência de Bases , Brasil , Estudos Transversais , Genótipo , Antígenos do Núcleo do Vírus da Hepatite B , Vírus da Hepatite B/imunologia , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
We investigated the effect of -174 G/C single-nucleotide polymorphism in the promoter region of the IL6 gene on plasma IL-6 levels and muscle strength, and the relationship between IL-6 levels and muscle strength in elderly women. The sample consisted of 199 elderly residents (73.0 ± 7.8 years old) from rest homes and the community in Belo Horizonte, MG, Brazil. -174 G/C polymorphism was determined by direct sequencing of the product by PCR, and plasma IL-6 concentrations were measured by ELISA. Muscle strength in the knee joint was evaluated using a Biodex System 3 Pro® isokinetic dynamometer. ANCOVA was used to determine the effect of polymorphism on IL-6 levels and muscle strength, and the Pearson correlation coefficient to assess the relationship between IL-6 levels and muscle strength. -174 G/C polymorphism was associated with the plasma IL-6 levels of elderly women (P < 0.01) since homozygotes for the G allele showed high IL-6 levels (GG 3.85 pg/mL, GC + CC 2.13 pg/mL). There was no association of polymorphism on muscle strength (P > 0.05). No association was found between IL-6 levels and knee extensor muscle (r = 0.087, P = 0.306) or flexor (r = -0.011, P = 0.894) strength. An interaction between -174 G/C polymorphism and housing conditions of the sample of elderly women was identified, with the effect of genotype on IL-6 levels being higher in the institutionalized elderly. These results support the evidence that -174 G/C polymorphism of the IL6 gene associates with individual variability of plasma IL-6 levels in elderly women.