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.

Prevalence of Dual-Positivity for Both Hepatitis B e Antigen and Hepatitis B e Antibody Among Hospitalized Patients with Chronic Hepatitis B Virus Infection

“…Second, the double-mutation A1762T/G1764A in the basal core promoter (BCP)/X overlap region was found to be one of the most common core promoter mutations, 18 which was positively correlated with the levels of ALT and AST, 19 , 20 the fluctuation of HBV DNA level, 20 , 21 and the progression of LDs, 22–25 and it can be a predictor of HBeAg-to-anti-HBe seroconversion. 23 A previous research showed that this mutation might be selected through CTL escape during the loss of immune tolerance.…”

Hepatitis B-related hepatocellular carcinoma: surveillance strategy directed by immune-epidemiology

“…Some risk factors for hepatocarcinogenesis have been studied in patients with HBV in Latin America. The most common HBV genotype in the region is F, which has been associated with early-age HCC among Alaska natives [32,33,37] . Furthermore, the HBV A1762T/G1764A double mutant strain, which is associated with HCC development, has been described in Latin American populations, though in variable frequencies [33,38] .…”