Hepatitis B virus in Buenos Aires, Argentina: genotypes, virological characteristics and clinical outcomes

Hepatitis B virus (HBV) is classified into eight major genotypes, A-H, which are geographically distributed worldwide. The aim of this work was to describe the clinical characteristics associated with the HBV genotypes circulating in Buenos Aires city. The study included 139 patients infected with HBV, whose clinical courses were classified as acute symptomatic self-limiting hepatitis, inactive carrier state and chronic active hepatitis (HBV e-antigen (HBeAg)-positive and HBeAg-negative). The HBV genotypes were determined in 128 patients by PCR-restriction fragment length polymorphism and phylogenetic analysis. Biochemical, virological, clinical and histological features were analysed. A differential distribution of genotypes between acute symptomatic and chronic infections was found. Among the acute cases, genotype F was predominant (65.2%, 30/46) and genotype D was rare (4.3%, 2/46), whereas among the chronic infections, a homogeneous distribution of genotypes A (26.8%, 22/82), D (31.7%, 26/82) and F (36.6%, 30/82), with an unusual presence of genotypes B (1.2%, 1/82) and C (3.7%, 3/82), was observed. Regarding the liver histology of chronically infected patients, genotype F tended to display higher histological activity indexes. Mutations related to HBV surface antigen immunoreactivity, antiviral resistance and HBeAg-negative status were studied. This work constitutes, to our knowledge, the first description of the clinical characteristics related to HBV genotypes in Argentina, where the distribution of genotypes in patients with acute infection has not been reported previously. Finally, it was established that genotype F is the prevalent genotype among the acute symptomatic infections in Buenos Aires city, and that it shows a tendency to cause an adverse disease outcome among the chronic cases.