Molecular genetic diversity of EBV and HHV6V: impact on viral load in coinfection

Aim. The aim of the study was to investigate molecular genetic diversity of Epstein-Barr virus (EBV) and human herpes virus 6B (HHV6B) and its influence on viral load in children of Nizhny Novgorod region during co-infection.

Materials and methods. 246 children with mononucleosis-like syndrome (MLS) and 118 healthy virus-carriers were examined. Based on serological and PCR studies, etiological agent in children with MLS and EBV and/or HHV6B carriage in healthy children were established, EBV and/or HHV6V DNA content in blood leukocytes was determined. EBV and HHV6B genotyping was performed based upon amino acid sequence of EBV LMP-1 protein fragment and nucleotide sequence of HHV6B U90 gene fragment.

Results. EBV + HHV6B manifest coinfection or healthy carriage was detected in 31% of children with MLS and 34% of healthy children, respectively. Circulation of 4 EBV genovariants (B95-8, NC, China-1, and MEDneg) and 4 HHV6B genovariants (GV1a, GV2a, GV2b, and GV2e) was detected under monoinfection, 11 combinations of virus genovariants – under coinfection. Under monoinfection and coinfection, EBV/B95-8, EBV/NC, HHV6B/GV2b and HHV6B/GV2e genovariats dominated. In children with MLS, EBV DNA content decreased by 230-276 copies/10⁵ cells under EBV/ B95-8 coinfection compared to monoinfection regardless of HHV6B genovariants. Under EBV/B95-8 + HHV6B/GV2b or EBV/B95-8 + HHV6B/GV2e coinfection HHV6B viral load decreased by 1.3 copies/10⁵ cells. Under EBV/B95-8 + HHV6B/GV1a and EBV/B95-8 + HHV6B/GV2e coinfection HHV6B and EBV DNA content interconnected in linear-logarithmic manner.

Conclusion. Molecular genetic polymorphism of EBV and HHV6B influenced on viral DNA content in blood leukocytes of children with MLS during coinfection.

1. Damania B., Kenney S.C., Raab-Traub N. Epstein-Barr virus: Biology and clinical disease // Cell. 2022; 185(20): 3652–3670.

2. Leung A.K.-C., Lam J.M.-C., Barankin B et al. Roseola Infantum: An Updated Review // Curr Pediatr Rev. 2024; 20(2): 119–128.

3. Aimola G., beythien G., Aswad A, Kaufer B.B. Current understanding of human herpesvirus 6 (HHV-6) chromosomal integration //Antiviral Res. 2020; 176: 104720.

4. Collin V., Flamand L. The importance of telomeres in human herpesvirus-6A/B infections // Med Sci (Paris). 2022; 38(2): 168–176.

5. La Frazia S., pauciullo S., Zulian V., Garbuglia A.R. Viral Oncogenesis: Synergistic Role of Genome Integration and Persistence // Viruses. 2024; 16(12): 1965.

6. Goncharova E.V., Senyuta N.B., Smirnova K.V., Shcherbak L.N. et al. Epstein-Barr virus (eBV) in Russia: infection of the population and analysis of the LMP1 gene variants in patients with EBV-associated pathologies and healthy individuals // Voprosy virusologii. 2015; 60 (2): 11–17. (In Russian)

7. Mishankina O.N., Rychkova O.A., Khanipova L.V., Usenko D.V. Diverse and insidious human herpesvirus 6A/B: how to find and neutralize it? // Infekc. bolezni (Infectious diseases). 2020; 18(3): 190–196. (In Russian).

8. Demina O.I., Chebotareva T.A., Mazankova L.N., Tetova V.B. et al. Infectious mononucleosis in children: clinical and laboratory characteristics depending on the disease etiology and phase of infection // Infekc. bolezni (Infectious diseases). 2020; 18(3): 62–72. (In Russian).

9. Lysenkova M. Yu, Melekhina E.V., Karazhas N.V., Svitich O.A. et al. The clinical and epidemiological features of HHV-6A and HHV-6B infections in children of Moscow // Detskie Infektsii=Children’s Infections. 2019; 18(1):11-16. (In Russian).

10. Melekhina E.V., Lysenkova M.Yu., Svitich O.A., Muzyka A.D. et al. Features o f HHV-6A and HHV-6B infections in children living in the Moscow Region // Eüpidemiologiü i infekcionnye bolezni. Aktual’nye voprosy. 2018; (2): 42–49. (In Russian).

11. Melekhina E.V., Muzyka A.D., Kalugina M.Y., Chugunova O.L. et al. Course of infection caused by Herpes virus type 6 in children with acute respiratory diseases // Pediatriay – Zhurnal im G.N. Speranskogo. 2016; 95(2): 30–37. (In Russian).

12. Tian N.S., Babachenko I.V., Goleva O.V., Orlova E.D. et al. Clinical, laboratory and virological aspects in infectious mononucleosis of EBV- and HHV-6 etiology in children // Detskie Infektsii=Children’s Infections. 2023; 22(4):34-38. (In Russian).

13. Dutlova D.V., Urazova O.I., Pomogaeva A.P. Clinical and laboratory features of infectious mononucleosis in children depending on the etiology of the disease // Detskie Infektsii=Children’s Infections. 2016; 15(1): 30–34. (In Russian).

14. Hoover K., Higginbotham K. Epstein-Barr Virus. – Treasure Island (FL): StatPearls Publishing, 2025.

15. King O., Al Khalili Y. Herpes Virus Type 6. – Treasure Island (FL): StatPearls Publishing, 2024.

16. Kramar’, L.V. Ocenka pokazatelej obshchego analiza krovi u detej pri infekcionnom mononukleoze razlichnoj etiologii / L.V. Kramar’, O.A. Karmuhina // Sovremennye problemy nauki i obrazovaniya. 2012; (6). (In Russian).

17. Peddu V., Dubuc I., Gravel A. et al. Inherited Chromosomally Integrated Human Herpesvirus 6 Demonstrates Tissue-Specific RNA Expression In Vivo That Correlates with an Increased Antibody Immune Response // J Virol. 2019; 94(1): e01418-19.

18. Miranda J.L. Single-Cell Transcriptomics of Epstein-Barr Virus and Human Herpesvirus 6 Coinfection // Microbiol Resour Announc. 2023; 12(7): e0034223.

19. Meier U.-C., Cipian R.C., Karimi A. et al. Cumulative Roles for Epstein-Barr Virus, Human Endogenous Retroviruses, and Human Herpes Virus-6 in Driving an Inflammatory Cascade Underlying MS Pathogenesis // Front Immunol. 2021; 12: 757302.

20. Yaroslavtseva N.G., Tikhomirov D.S.,.Romanova T.Yu., Ignatova E.N. et al. Laboratory diagnostics of active and latent HHV 6-infection in patients with hematological malignancies. Voprosy Virusologii (Problems of Virology, Russian journal). 2018; 63(2): 84-90. (In Russian).

21. Edwards R.H., Seillier-Moiseiwitsch F., Raab-Traub N. Signature amino acid changes in latent membrane protein 1 distinguish Epstein-Barr virus strains // Virology. 1999; 261(1): 79–95.

22. Alanazi A.E., Alhumaidy A.A., Almutairi H. et al. Evolutionary analysis of LMP-1 genetic diversity in EBV-associated nasopharyngeal carcinoma: Bioinformatic insights into oncogenic potential // Infect Genet Evol. 2024; 120: 105586.

23. Alves P., Rohan P., Hassan R., Abdelhay E. Spatial Dispersal of Epstein-Barr Virus in South America Reveals an African American Variant in Brazilian Lymphomas // Viruses. 2022; 14(8): 1762.

24. Mitra B., Beri N.R., Guo R. et al. Characterization of target gene regulation by the two Epstein-Barr virus oncogene LMP1 domains essential for B-cell transformation // MBio. 2023; 14(6): e0233823.

25. Jaworska J., Gravel A., Flamand L. Divergent susceptibilities of human herpesvirus 6 variants to type I interferons // Proceedings of the National Academy of Sciences. 2010; 107(18): 8369–8374.

26. Popkova M.I., Utkin O.V., Bryzgalova D.A., Senatskaia A.O. et al. Methodological approaches to differential detection of EBV1/EBV2 and HHV6A/HHV6B in saliva // Russian Journal of Infection and Immunity = Infektsiya i immunitet. 2022; 12(3): 461–474. (In Russian).

27. Popkova M.I., Utkin O.V., Filatova E.N., Bryzgalova D.A. et al. Molecular genetic characterization of the Epstein– Barr virus: a relationship with the clinical features of pediatric infectious mononucleosis // Russian Journal of Infection and Immunity = Infektsiya i immunitet. 2023; 13(3): 481–496. (In Russian).

28. Yu S., Yang Q., Wu J. et al. Clinical application of Epstein-Barr virus DNA loads in Epstein-Barr virus-associated diseases: A cohort study // J Infect. 2021; 82(1): 105–111.

29. Popkova M.I., Filatova E.N., Soboleva E.A., Bryzgalova D.A. et al. Diagnostic value of Epstein – Barr virus DNA quantification in blood leukocytes in children with infectious mononucleosis // Zurnal infectologii. 2022; 10: 17-21. (In Russian).

30. Melehina E.V., Nikolaeva S.V., Soldatova E. Ju., Muzyka A.D. Human herpesvirus 6 variant A/B infections in child population // RMJ. 2019; 10:17–21. (In Russian).