Human herpesvirus 6

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Human herpesvirus 6 (HHV-6) is a set of two closely related herpesviruses, HHV6-A and HHV6-B. Infection is extremely common and usually occurs at an early age. 64-83% of infants are infected by age 13 months.[1] HHV-6 has an affinity for leukocytes and nervous tissue, especially the olfactory bulb tissues[2], from which it is thought to disseminate to other parts of the brain. After infection the virus remains latent but can reactivate asymptomatically even in healthy individuals.

HHV-6 has been found to activate Epstein-Barr virus from latency. Conversely, the presence of EBV renders B cells more susceptible to HHV-6 infection.[3]

In human disease[edit | edit source]

HHV-6 has been implicated as a contributing factor to a number of neurological diseases including multiple sclerosis[4], chronic fatigue syndrome[5] and epilepsy, as well as fibromyalgia and AIDS.

Multiple sclerosis[edit | edit source]

HHV-6 has been found in the oligodendrocytes of plaques in MS patients but not in healthy tissue.[6]

Antivirals may have some therapeutic benefit. A randomized, placebo-controlled double-blind study found that acyclovir reduced the exacerbation rate in relapsing-remitting MS patients.[7]. Valacyclovir reduced new lesions in patients with high disease activity.[8]

Cancer[edit | edit source]

Like Epstein-Barr virus, HHV-6 is associated with lymphomas and carcinomas.[9]

Chronic fatigue syndrome[edit | edit source]

One study found a higher prevalence of past HHV-6 infection in chronic fatigue syndrome patients but with a low viral load that did not suggest reactivation.[10] Several studies have found that active infection is more common in CFS patients than healthy controls.[11]

Antivirals[edit | edit source]

There have been no controlled trials of antivirals for HHV-6. Those used clinically are the drugs used for human cytomegalovirus: ganciclovir, valganciclovir, and to a lesser extent acyclovir.

Notable studies[edit | edit source]

Learn more[edit | edit source]

See also[edit | edit source]

References[edit | edit source]

  4. Pietiläinen-Nicklén J, Virtanen JO, Uotila L, Salonen O, Färkkilä M, Koskiniemi M. (2014). HHV-6-positivity in diseases with demyelination. Journal of Clinical Virology, 61 (2):216-9. doi: 10.1016/j.jcv.2014.07.006. Epub 2014 Jul 21. Rerieved from
  12. Aoki, R; Kobayashi, N; Suzuki, G; Kuratsune, H; Shimada, K; Oka, N; Takahashi, M; Yamadera, W; Iwashita, M; Tokuno, S; Nibuya, M; Tanichi, M; Mukai, Y; Mitani, K; Kondo, K; Ito, H; Nakayama, K (2016), "Human herpesvirus 6 and 7 are biomarkers for fatigue, which distinguish between physiological fatigue and pathological fatigue", Biochemical and Biophysical Research Communications, 478 (1): 424-30, doi:10.1016/j.bbrc.2016.07.010, PMID 27396623 

The information provided at this site is not intended to diagnose or treat any illness.
From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history.