Acute and chronic HBV infection in central Argentina: High frequency of sub-genotype F1b, low detection of clinically relevant mutations and first evidence of HDV

Abstract

IntroductionGenomic analysis of hepatitis B virus (HBV) identifies phylogenetic variants, which may lead to distinct biological and clinical behaviors. The satellite hepatitis D virus (HDV) may also influence clinical outcomes in patients with hepatitis B. The aim of this study was to investigate HBV genetic variants, including clinically relevant mutations, and HDV infection in acute and chronic hepatitis B patients in central Argentina.MethodsA total of 217 adult HBV infected patients [acute (AHB): n = 79; chronic (CHB): n = 138] were studied; 67 were HBV/human immunodeficiency virus (HIV) coinfected. Clinical and demographic data were obtained from medical records. Serological markers were determined. Molecular detection of HBV and HDV was carried out by RT-Nested PCR, followed by sequencing and phylogenetic analysis.ResultsOverall, genotype (gt) F [sub-genotype (sgt) F1b] was the most frequently found. In AHB patients, the gts/sgts found were: F1b (74.7%) > A2 (13.9%) > F4 (7.6%) > C (2.5%) > A1 (1.3%). Among CHB patients: F1b (39.1%) > A2 (23.9%) > F4 (18.2%) > D (9.4%) > C and F6 (3.6% each) > A1, A3 and B2 (0.7% each). The distribution of sgt A2 and gt D was significantly different between HBV mono and HBV/HIV coinfected patients [A2: 15.9% vs. 35.7% (p < 0.05), respectively and D: 14.6% vs. 1.8% (p < 0.05), respectively]. Mutation frequency in basal core promoter/pre-Core (BCP/pC) region was 35.5% (77/217) [AHB: 20.3% (16/79), CHB: 44.2% (61/138)]. In the open reading frame (ORF) S, mutations associated with vaccine escape and diagnostic failure were detected in 7.8% of the sequences (17/217) [AHB: 3.8% (3/79), CHB: 10.1% (14/138)]. ORF-P amino acid substitutions associated with antiviral resistance were detected in 3.2% of the samples (7/217) [AHB: 1.3% (1/79), CHB 4.3%, (6/138)]. The anti-HDV seropositivity was 5.2% (4/77); one sample could be sequenced, belonging to gt HDV-1 associated with sgt HBV-D3.DiscussionWe detected an increase in the circulation of genotype F in Central Argentina, particularly among AHB patients, suggesting transmission advantages over the other genotypes. A low rate of mutations was detected, especially those with antiviral resistance implications, which is an encouraging result. The evidence of HDV circulation in our region, reported for the first time, alerts the health system for its search and diagnosis.

Breakthrough infection by hepatitis B virus in a vaccinated blood donor: An emerging threat for transfusion safety in low‐endemic countries?

“…3 Also, a recent study showed a mean age of 41.7 (±11.4) years for acute HBV infection. 4 These data show that the vaccine was indeed effective in preventing HBV disease in vaccinated people (born after 1992) since the recorded data regarding acute infections corresponded to individuals with clinical symptoms caused by HBV. Nonetheless, our donor not only belonged to the age group reached by HBV-universal vaccination but he also had protective levels of anti-HBs (>10 mIU/mL).…”

“…Although most significant HBV surface mutations related to vaccine escape and diagnostic failure could not be assessed because the S gene could not be amplified, whether significant HBsAg mutations may be present in the innovative case is a limitation to further discuss. However, these mutations were not identified among gt F in the cohort of HBV‐infected patients evaluated by Castro et al, suggesting that at this moment, mutations in the ORF‐S are not a matter of major concern in this region 4 …”

“…Reference sequences from each genotype and subgenotype available in the GenBank database were included with their accession number. Sequences previously obtained from Córdoba were also included in the analysis 4 . The numbers next to each node correspond to bootstrap values obtained with 1000 replicates.…”

“…Direct nucleotide sequencing reaction in both directions was carried out using a 3500xL Genetic Analyzer (Applied Biosystems), by means of a locally standardized and validated protocol with the same primers used in amplification stages. The amino acid sequence was analyzed as described by Castro et al 4 HBV genotypes (gts) were determined by analyzing this amplified sequence by phylogenetic analysis using reference sequences obtained from the GeneBank database.…”

“…Rarely, cases of HBV‐vaccination breakthrough have been documented, mainly involving immune escape variants that carry mutations in the major antigenic region of HBV surface antigen (HBsAg) 1,2 . Argentina is considered an HBV low‐endemic country, 3 with low detection of clinically relevant mutations 4 . However, profiles of atypical infection that challenge transfusion safety have been described 5 and although mutants involved in immune evasion have been found in very low frequency among patients with acute hepatitis B in a recent large cohort from Argentina, 4 HBV represents a continuous threat for transfusion safety.…”