Increased prevalence of varicella zoster virus DNA in cerebrospinal fluid from patients with multiple sclerosis

In order to investigate the possible involvement of viruses in Multiple Sclerosis (MS), the study evaluated the presence of viral genomic sequences in cerebrospinal fluid (CSF), as markers of viral replication within the central nervous system (CNS). A total of 85 CSF samples were collected from 38 MS patients, 28 patients with other neurological diseases and 19 subjects without neurological diseases. Using nested-PCR, the investigation focused on the presence of human herpes virus DNA, including herpes simplex virus 1 (HSV-1) and 2 (HSV-2), the Epstein-Barr virus (EBV), varicella zoster virus (VZV), human cytomegalovirus (HCMV), human herpes virus 6 (HHV-6) and JC virus (JCV). All the CSF samples from the individuals without neurological diseases were negative for viral DNA. Genomic sequences of HSV-1, HCMV, EBV, HHV6, and JCV were found in patients with MS and other neurological diseases without significant differences between the two groups. VZV DNA was detected more frequently (P < 0.05) in the MS group (31.6%), particularly among the relapsing-remitting MS patients (43.5%), compared with patients with other neurological diseases (10.7%). In addition, the results indicated that JCV and HHV-6 were replicating actively in the CNS of a small, but significant number of patients with MS and other neurological diseases. Most importantly, the study revealed a high frequency of VZV DNA in the CSF of patients with MS, suggesting a possible role of this virus in the pathogenesis of MS.