Source: Drug Delivery  |  Posted 9 years ago

Human herpes virus-6 (HHV-6) reactivation is implicated in the exacerbation of multiple sclerosis.

Reactivation may occur through modulation of IL-12 synthesis, say researchers based at the University of Latvia and the Latvian Medical Academy, Riga, Latvia. They report finding the correlation between HHV-6 reactivation and disease activity in relapsing/remitting and secondary progressive multiple sclerosis.

The risk of an exacerbation of multiple sclerosis was significantly higher in patients with active HHV-6 infection than in patients with latent infection, the researchers said.

They studied the frequency of HHV-6 genomic sequences in peripheral blood mononuclear cells, the incidence of plasma viraemia and the transcription of viral mRNA in peripheral blood mononuclear cells. They also investigated the presence of antiviral IgM and IgG class antibodies in the plasma of 16 relapsing/remitting and secondary progressive multiple sclerosis patients.

The researchers compared the presence of these antibodies to clinical manifestations of the disease, magnetic resonance imaging of brain, and serum interleukin 12 concentrations.

The prevalence of HHV-6 infection was significantly higher in patients with multiple sclerosis (61.5%) than in patients with other neurological diseases (28.6%) or in blood donors (28.7%).

HHV-6 reactivation was found during periods of disease activity with gadolinium-enhancing lesions on magnetic resonance imaging in both relapsing/remitting and secondary progressive multiple sclerosis (76.9%).

In patients with active multiple sclerosis, serum concentrations of IL-12 were significantly higher in those whose HHV-6 infection was active than in those with latent infection.