In order to investigate the possible role of EBV systemic infection in the pathogenesis of MS, or to the release of free virus following lytic infection. Technical issues related to the sensitivity and specificity of the detection methods were partly held responsible for the lack of Ganoderic-acid-G unequivocal proof on the role of EBV infection in MS. Although the presence of EBV PCR DNA in CSF is an indirect measure of the events occurring in brain tissue, its detection is somewhat relevant to the controversy. This study aimed at providing evidence for the presence of EBV DNA in CSF and peripheral blood samples of RRMS patients, as compared to those of patients with other neurological diseases, by means of a validated, highly standardized and reproducible methods for viral nucleic acid extraction and molecular quantitative detection. All samples were processed rapidly after collection and stored under appropriate conditions prior to sample analysis. In order to improve recovery of hypothetical small numbers of viral particles present in the CSF a larger volume of sample was analyzed as compared to most previous studies. CSF and peripheral blood samples were also further separated in cell-free and cell-associated components prior to EBV DNA detection, in order to distinguish between possible latent and lytic EBV infections. Our results showed similar EBV DNA positivities in cell-free and cell-associated CSF from RRMS and NIND subjects, while OIND subjects were all negative. Generally, slightly higher positivity rates were obtained when compared to previous investigations carried out on CSF samples from MS cases and controls. These differences could be explained by the larger volume of CSF sample analyzed, the Isoacteoside improved efficiency in viral nucleic acid recovery, as a result of the DNA extraction method used, and the higher sensitivity of the standardized EBV molecular detection assay used in our study, allowing detection down to 10 copies/reaction or 120 copies/ml. However, in spite of the improved viral detection and quantification methods, this study did not provide evidence for an association between EBV and RRMS. PBMC and plasma EBV viral load were also determined in this study as a measure of viral lytic infection and in order to evaluate if peripheral viral activity corresponded to disease activity. As observed in the CSF, in the peripheral blood samples positive for EBNA-1 gene, EBV viral load was not significantly different in RRMS patients as compared to OIND and NIND subjects. These results are in keeping to those obtained in previous studies, although higher EBV positivities in PBMC were observed by Lindsey et al based on the presence of BamHIW repeat sequence. In conclusion, this study used appropriately validated methods for both the pre-analytical and analytical detection of EBV DNA in order to provide improved standardized viral 
detection from different clinical samples. In spite of this improved methodological aspects and considering the relatively low sample size, our study confirms previous results showing lack of any significant difference in CSF and peripheral blood EBV DNA positivities and viral load between RRMS patients and the control groups.