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Human herpesvirus 6 and 7 reactivation and disease activity in multiple sclerosis

Zaiga Nora-Krukle1, Svetlana Chapenko, Inara Logina

  • 1August Kirchenstein Institute of Microbiology and Virology, Riga Stradins University, Latvia. zaiga.nora@gmail.com

Medicina (Kaunas, Lithuania)
|December 22, 2011
PubMed
Abstract

Insights

Human herpesviruses 6 and 7 (HHV-6 and HHV-7) reactivation may worsen multiple sclerosis (MS) disease activity. This reactivation is linked to increased levels of IL-12 and TNF-α, suggesting a role in MS exacerbation.

Area of Science:

  • Virology
  • Immunology
  • Neurology

Background:

  • Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system.
  • Human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) are common viruses with suspected links to MS pathogenesis.

Purpose of the Study:

  • To investigate the association between HHV-6 and HHV-7 reactivation and MS disease activity.
  • To examine the relationship between viral reactivation and the production of cytokines IL-12 and TNF-α in MS patients.

Main Methods:

  • Nested polymerase chain reaction (PCR) was used to detect plasma viremia of HHV-6 and HHV-7.
  • Reverse transcriptase-polymerase chain reaction (RT-PCR) assessed viral mRNA transcription in peripheral blood mononuclear cells.
  • Serum concentrations of IL-12 and TNF-α were measured using enzyme-linked immunosorbent assay (ELISA).

Main Results:

  • HHV-6 and HHV-7 reactivation were detected in MS patients during relapse.
  • Viral reactivation correlated with higher serum concentrations of IL-12 and TNF-α compared to latent infections.
  • HHV-6 mRNA transcription was observed even in the absence of detectable viremia during relapse.

Conclusions:

  • Reactivation of HHV-6 and HHV-7 may contribute to the exacerbation of MS.
  • The observed increase in IL-12 and TNF-α suggests a Th1 lymphocyte-mediated mechanism in MS flares.
  • These findings highlight a potential role for herpesviruses in MS disease activity.

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