[Identification by enzyme immunoassay of escape mutants S143L and G145R of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus)].

INTRODUCTION: The achievement of the goal of the World Health Organization to eliminate viral hepatitis B by 2030 seems to be problematic partly due to the presence of escape mutants of its etiological agent, hepatitis B virus (HBV) (<i>Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus</i>), that are spreading mainly in the risk groups. Specific routine diagnostic assays aimed at identification of HBV escape mutants do not exist.The study aimed the evaluation of the serological fingerprinting method adapted for routine detection of escape mutations in 143 and 145 aa positions of HBV surface antigen (HBsAg). MATERIAL AND METHODS: HBV DNA from 56 samples of HBsAg-positive blood sera obtained from donors, chronic HBsAg carriers and oncohematology patients has been sequenced. After the identification of mutations in HBsAg, the samples were tested in the enzyme-linked immunosorbent assay (ELISA) kit «Hepastrip-mutant-3K¼. RESULTS AND DISCUSSION: Escape mutations were detected mainly in patients with hematologic malignancies. Substitutions in 143 and 145 aa were found in 10.81% and in 8.11% of such patients, respectively. The G145R mutation was recognized using ELISA kit in almost all cases. The kit specifically recognized the S143L substitution in contrast to the S143T variant. The presence of neighbor mutation D144E can be assumed due to it special serological fingerprint. CONCLUSION: ELISA-based detection of escape mutations S143L, D144E and G145R can be used for routine diagnostics, especially in the risk groups. The diagnostic parameters of the kit can be refined in additional studies. This immunoassay and methodology are applicable for the development and quality control of vaccines against escape mutants.

[Search for RNA of the hepatitis E virus autochthonous for Russia in the most likely infection sources].

The research carried out for 30 years from the moment of hepatitis E virus (HEV) discovery has proved the presence of the autochthonous HEV in non-endemic areas: Europe and Russia. Monitoring of the HEV antibodies (anti-HEV) among the Russian population has revealed regions with increased seroprevalence that testifies to high probability of local HEV infection in these areas. Contact with HEV can represent special danger for patients of the risk groups. In this work, the blood sera testing was carried out in order to assess the anti-HEV presence among these contingents (groups). Seropositive sera from the patients from the regions with high anti-HEV seroprevalence, risk groups patients, samples with high probability of HEV occurrence including the animals as possible reservoir, have been used for RNA extraction. The developed system of HEV RNA detection both in real-time RT-PCR and in a nested PCR variant has confirmed its sensitivity to the synthetic reference templates and positive control samples in commercial test system (Genesig, Great Britain). HEV RNA was absent in all tested samples. This indicates a low frequency of the autochthonous HEV carriage occurrence. Sampling enlargement to tens of thousands persons is necessary for significant HEV RNA detection.