Genotypic Diversity of Hepatitis C Virus in Tuberculosis Patients in the Tomsk Region

Relevance . People with tuberculosis (TB) are at an increased risk of spreading parenteral viral hepatitis, including hepatitis C virus (HCV). Hepatitis C in tuberculosis patients can often be detected only as a result of laboratory tests. Some of the anti-tuberculosis drugs have a pronounced hepatotoxic effect, which can lead to severe liver damage, especially in cases of combined TB and HCV infection. Aim . Determination of genotypic diversity and molecular genetic characteristics of HCV isolates isolated from patients infected with tuberculosis in the Tomsk region. Materials and methods . The study was conducted on 117 blood serum/plasma samples obtained from patients infected with tuberculosis. The identified HCV isolates were genotyped by amplifying a fragment of the core gene in two-round PCR followed by determination of the nucleotide sequences of the resulting amplicons. Viral load was determined by quantitative RT-PCR. Results and discussion . The following distribution of subtypes in the studied sample was revealed: 1b (47.0%; 95% CI: 38.2–56.0), 3a (32.5%; 95% CI: 24.7–41.3), 1a (18.0%; 95% CI: 12.1–25.8) and recombinant 2k/1b (2.5%; 95% CI: 0.9–7.2). Among the variants of subtype 1b, polymorphisms in the core gene were identified, associated with resistance to interferon treatment: among 35 isolates, the L91M mutation was detected (63.6%; 95% CI: 31.4–56.7), substitutions at position R70Q were detected in 19 isolates /H (34.6%; 95% CI: 7.6–26.1). Both substitutions were found in 11 isolates (20.0%; 95% CI: 11.5–32.3). No differences were found in the distribution of subtypes between the four age groups (under 36, 36–40, 41–45, over 45). Significant differences were revealed (Pearson's χ² = 9.38; p = 0.025) in the distribution of subtypes between the examined men and women. In men, subtype 1b predominated, in women, subtype 3a predominated and there were practically no people infected with subtype 1a, unlike male patients. Conclusion . HCV research among tuberculosis-infected people is important for choosing the most appropriate treatment tactics for patients, preventing complications of co-infection, as well as for planning and implementing preventive measures.