Activation of human herpesviruses 6 and 7 in patients with chronic fatigue syndrome

J Clin Virol. 2006 Dec;37 Suppl 1:S47-51.

Activation of human herpesviruses 6 and 7 in patients with chronic fatigue syndrome.

Chapenko S, Krumina A, Kozireva S, Nora Z, Sultanova A, Viksna L, Murovska M. August Kirchenstein Institute of Microbiology and Virology, Riga Stradins University, Ratsupites St.1, Riga, LV-1067, Latvia.

BACKGROUND: Human herpesvirus 6 (HHV-6) and 7 (HHV-7) have been suggested as possible triggering agents for chronic fatigue syndrome (CFS). OBJECTIVES: To determine the possible association of HHV-6 and HHV-7 infections with CFS. STUDY DESIGN: The prevalence of latent/persistent and active viral infections by nPCR, characteristic of HHV-6 variants using restriction endonuclease analysis and changes of lymphocyte subsets in peripheral blood by laser flow-cytometry in 17 CFS patients was examined. In addition, 12 patients with unexplained chronic fatigue and 20 blood donors (BD) were studied. RESULTS: No difference in prevalence of latent/persistent single viral infections between the patients and BD was found but dual infection rate was significantly higher in CFS patients. Active HHV-6 and dual (HHV-6 + HHV-7) infections were detected in CFS patients only and frequency of HHV-7 reactivation was also significantly higher in these patients. HHV-6 variant B was predominant in CFS patients (12/13). The changes of immunological parameters in CFS patients with active dual infection were characterized by significant decrease of CD3+ and CD4+ T cells, significant increase of CD95+ cells and decrease of CD4+/CD8+ ratio. CONCLUSIONS: HHV-6 and HHV-7 may be involved in the pathogenesis of CFS and reactivation of both viruses may provoke changes in the phenotype of circulating lymphocytes.

PMID: 17276369 [PubMed - in process]

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