Comparative Immunovirological Investigations of HHV-6, HHV-7, and HHV-8 in Multiple Schlerosis (MS), Other Neurological Disorders (OND), and Healthy Donors (HD)

IMMUNOVIROLOGICAL INVESTIGATIONS OF HHV-6, HHV-7, AND HHV-8 IN

MULTIPLE SCLEROSIS (MS), AND OTHER NEUROLOGICAL DISORDERS (OND),

al. (1995), Soldan et al. (1997), and Ablashi et al. (1998)

support the concept that HHV-6 is involved in the pathogenesis of

MS. We recently investigated the possible association of HHV-6

and HHV-7 (beta herpesviruses) and HHV-8, better known as

Kaposi’s sarcoma herpesvirus (KSHV) (a gamma-2 herpesvirus)

with MS. Cerebral spinal fluids (CSF), plasma, and sera, as well

as peripheral blood mononuclear cells (PBMC) from patients and

normal healthy donors, were analyzed for the presence of IgM

antibodies, viral DNA, and viral antigens or viruses. Greater

than 55% of the MS patients’ sera contained IgM antibody to

HHv-6 early protein (p41/38) compared to 17% of HD and >75% of

these MS sera also contained IgM antibody to HHV-6 late antigens.

However, only 14.3% CSF samples and 13.3% of the plasma samples

contained HHV-6 DNA. Approximately 75% of the PBMC samples tested

from MS patients when tested by IFA with HHV-6 Mabs expressed

HHV-6 antigens, and 20% of them also expressed HHV-7 antigens,

but none of them expressed HHV-8 DNA or antigens. Only 16.7% of

the PBMC from OND were PCR positive for HHV-6 and 205 were also

positive for HHV-7. None of the PBMC contained HHV-8 DNA or

antigens. A few sera from HD contained HHV-6 IgM antibody

(13.6%), but no HHV-6 DNA was detected in the plasma from these

individuals. However, HHV-6 Variant A was isolated from 2/22 HD

PBMC (9.1%). No HHV-8 DNA was detected in these HD PBMCs. Only

1/22 healthy donors’ sera contained HHV-8 IgG antibody

(4.5%). HHV-7 DNA was detected in 9/22 HD PBMC (36.2%). HHV-7 IgM

association of HHV-6 with MS, but neither HHV-7 nor HHV-8 showed

any association. No association of HHV-6, HHV-7, or HHV-8 was