The persistent viral infections in the development and severity of myalgic encephalomyelitis/chronic fatigue syndrome

Santa Rasa-Dzelzkaleja (Coresponding Author), Angelika Krumina, Svetlana Capenko, Zaiga Nora-Krukle, Sabine Gravelsina, Anda Vilmane, Lauma Ievina, Yehuda Shoenfeld, Modra Murovska

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multifactorial disease with an unexplained aetiology in which viral infections are possible trigger factors. The aim of this study was to determine the involvement of human herpesvirus (HHV)-6A/B, HHV-7, and parvovirus B19 (B19V) in the etiopathogenesis of ME/CFS.

METHODS: 200 patients with clinically diagnosed ME/CFS and 150 apparently healthy individuals were enrolled in this study. Single-round, nested, and quantitative real-time polymerase chain reactions (PCR) were used to detect the presence and load of HHV-6A/B, HHV-7, and B19V. HHV-6A and HHV-6B were distinguished by PCR and restriction analysis. Immunoenzymatic assays were applied to estimate the presence of virus-specific antibodies and the level of cytokines.

RESULTS: HHV-6A/B, HHV-7, and B19V specific antibodies were detected among patients and healthy individuals in 92.1% and 76.7%, 84.6% and 93.8%, and 78% and 67.4% of cases. HHV-6B had 99% of HHV-6 positive patients. Latent HHV-6A/B, HHV-7, and B19V infection/co-infection was observed in 51.5% of the patients and 76.7% of the healthy individuals, whereas active-45% of the ME/CFS patients and 8.7% of healthy individuals. HHV-6A/B load in patients with a persistent infection/co-infection in a latent and active phase was 262 and 653.2 copies/106 cells, whereas HHV-7 load was 166.5 and 248.5 copies/106 cells, and B19V-96.8 and 250.8 copies/106 cells, respectively. ME/CFS patients with persistent infection in an active phase had a higher level of pro-inflammatory cytokines (interleukin(IL)-6, tumor necrosis factor-alpha(TNF-α) and IL-12) and anti-inflammatory (IL-10) than with a persistent infection in a latent phase. A significant difference was revealed in the levels of TNF-α, IL-12, and IL-10 among the patient groups without infection, with latent infection/co-infection, active single, double and triple co-infection. The levels of TNF-α, IL-12, and IL-10 are significantly higher in patients with severe compared with a moderate course of ME/CFS.

CONCLUSIONS: Significantly more persistent HHV-6A/B, HHV-7, and B19V infection/co-infection in an active phase with a higher viral load and elevated levels of pro- and anti-inflammatory cytokines among patients with ME/CFS than healthy individuals indicate the importance of these infections/co-infections in ME/CFS development. The presence of these infections/co-infections influences the ME/CFS clinical course severity.

Original languageEnglish
Article number33
Pages (from-to)33
Number of pages1
JournalJournal of Translational Medicine
Issue number1
Publication statusPublished - 18 Jan 2023


  • Humans
  • Fatigue Syndrome, Chronic
  • Interleukin-10
  • Coinfection
  • Tumor Necrosis Factor-alpha
  • Persistent Infection
  • Virus Diseases
  • Cytokines
  • Interleukin-12
  • Myalgic encephalomyelitis/chronic fatigue syndrome,
  • HHV-6B
  • HHV-7
  • HHV-6A
  • Human parvovirus B19

Field of Science*

  • 3.2 Clinical medicine
  • 3.1 Basic medicine

Publication Type*

  • 1.1. Scientific article indexed in Web of Science and/or Scopus database


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