Identification of hepatitis B virus A1762T/G1764A double mutant strain in patients in Southern Brazil

Abstract Infection by hepatitis B virus (HBV) is a worldwide public health problem. Chronic HBV infection with high viral replication may lead to cirrhosis and/or hepatocellular carcinoma. Mutant HBV strains, such as the HBV A1762T/G1764A double mutant, have been associated with poor prognosis and higher risk of the patient for developing cirrhosis and/or hepatocellular carcinoma. This study analyzed the presence of the HBV A1762T/G1764A double mutant in patients with chronic HBV and its association with clinical parameters such as viral load, aminotransferases, and HBV antigens. A total of 49 patients with chronic hepatitis B were included in the study, and the HBV A1762T/G1764A double mutant strain was detected in four samples (8.16%) by polymerase chain reaction followed by restriction fragment length analysis (PCR-RFLP). The viral load was not significantly different between patients with or without the double mutant strain (p = 0.43). On the other hand, carriers of the HBV A1762T/G1764A double mutant had higher levels of ALT (p = 0.0028), while AST levels did not differ between groups (p = 0.051). In this study, 75% of the samples with the HBV A1762T/G1764A double mutation were HBeAg negative and anti-HBe positive, reflecting seroconversion even though they still displayed high viral loads. Our study has shown that the HBV A1762T/G1764A double mutant strain circulates in Brazilian patients, and is associated with elevated levels of ALT and HBeAg seroconversion.

Frequency of the mdr1 gene polymorphism rs1045642 (c3435t) in hcv-hiv co-infected patients / Frequência do polimorfismo rs1045642 (C3435T) do gene MDR1 em pacientes coinfectados HCV-HIV

ABSTRACT Background Due to the high prevalence of co-infection by hepatitis C virus (HCV) and human immunodeficiency virus (HIV) and the severity of these infections, the understanding of the biological mechanisms involved in these processes, including viral behavior and host genetic profile, is of great importance for patient treatment and for public health policies.Some single nucleotide polymorphisms (SNPs) in the human genome, such as the SNP rs1045642 (C3435T) in the MDR1 gene, have been reported to be associated to the sustained virological response (SVR) to HCV treatment in HCV-HIV co-infected patients. Objective The present study analyzes the MDR1 gene C3435T polymorphism in HCV-HIV co-infected patients. Methods A total of 99 HCV-HIV patients were included in the study. The DNA was extracted from blood samples, and the SNP rs1045642 was assessed by Real Time PCR (qPCR). Risk factors for acquiring the virus and the SVR after HCV treatment with pegylated interferon-alpha and ribavirin were also analyzed. Results Among the patients, 54 (54.5%) were male and 45 (45.5%) were female. The average age was 46.1±9.8 years. The SVR after HCV treatment was 40%. The frequencies of MDR1 genotypes CC, CT and TT were 28.3%, 47.5% and 24.2%, respectively. Allele frequencies were 52% for the C allele and 48% for the T allele. No association was found for SNP rs1045642 (C3435T) regarding response to treatment (P=0.308). Conclusion - In this study, the C3435T polymorphism in the MDR1 gene appears not to be associated with SVR in HCV-HIV co-infected individuals.

RESUMO Contexto Em virtude da elevada prevalência da coinfecção pelos vírus da hepatite C (HCV) e da imunodeficiência humana (HIV) e às inúmeras complicações que esses vírus acarretam, é fundamental o maior entendimento do comportamento biológico dos mesmos. O polimorfismo de nucleotídeo único rs1045642 C3435T do gene de resistência a múltiplas drogas MDR1, no qual ocorre modificação do códon ATC para ATT, parece estar relacionado à resposta virológica sustentada ao tratamento do HCV em coinfectados HCV-HIV. Objetivo Mapear o polimorfismo C3435T do gene MDR1 em pacientes coinfectados HCV-HIV e correlacionar com dados clínicos e laboratoriais. Métodos Foram analisados 99 pacientes coinfectados HCV-HIV. A identificação molecular do polimorfismo de nucleotídeo único rs1045642 do gene MDR1 foi realizada pela técnica de PCR em tempo real (qPCR) alelo-específico com primers e sondas específicos para a identificação desse polimorfismo. Fatores de risco para a aquisição do HCV e a resposta virológica sustentada ao tratamento do HCV com interferon-alfa peguilado e ribavirina foram analisados. Resultados Dentre os pacientes avaliados, 54 (54,5%) eram do gênero masculino e 45 (45,5%) do gênero feminino. A média de idade foi de 46,1 anos (±9,8). As frequências dos genótipos CC, CT e TT foram 28,3%, 47,5% e 24,2% respectivamente, e as frequências alélicas foram 52% para alelo C e 48% para alelo T. Não houve associação entre o gene MDR1 e a resposta virológica sustentada (P=0,308). Conclusão Neste estudo, o polimorfismo C3435T no gene MDR1 não apresentou associação com a resposta virológica sustentada ao tratamento em indivíduos coinfectados HCV-HIV.