No abstract

Epstein-Barr virus (EBV) has been associated with multiple sclerosis (MS), however, most studies examining the relationship between the virus and the disease have been based on serologies, and if EBV is linked to MS, CD8+ T cells are likely to be involved as they are important both in MS pathogenesis and in controlling viruses. We hypothesized that valuable information on the link between MS and EBV would be ascertained from the study of frequency and activation levels of EBV-specific CD8+ T cells in different categories of MS patients and control subjects. We investigated EBV-specific cellular immune responses using proliferation and enzyme linked immunospot assays, and humoral immune responses by analysis of anti-EBV antibodies, in a cohort of 164 subjects, including 108 patients with different stages of MS, 35 with other neurological diseases and 21 healthy control subjects. Additionally, the cohort were all tested against cytomegalovirus (CMV), another neurotropic herpes virus not convincingly associated with MS, nor thought to be deleterious to the disease. We corrected all data for age using linear regression analysis over the total cohorts of EBV- and CMV-infected subjects. In the whole cohort, the rate of EBV and CMV infections were 99% and 51%, respectively. The frequency of IFN-gamma secreting EBV-specific CD8+ T cells in patients with clinically isolated syndrome (CIS) was significantly higher than that found in patients with relapsing-remitting MS (RR-MS), secondary-progressive MS, primary-progressive MS, patients with other neurological diseases and healthy controls. The shorter the interval between MS onset and our assays, the more intense was the EBV-specific CD8+ T-cell response. Confirming the above results, we found that EBV-specific CD8+ T-cell responses decreased in 12/13 patients with CIS followed prospectively for 1.0 +/- 0.2 years. In contrast, there was no difference between categories for EBV-specific CD4+ T cell, or for CMV-specific CD4+ and CD8+ T-cell responses. Anti-EBV-encoded nuclear antigen-1 (EBNA-1)-specific antibodies correlated with EBV-specific CD8+ T cells in patients with CIS and RR-MS. However, whereas EBV-specific CD8+ T cells were increased the most in early MS, EBNA-1-specific antibodies were increased in early as well as in progressive forms of MS. Our data show high levels of CD8+ T-cell activation against EBV--but not CMV--early in the course of MS, which support the hypothesis that EBV might be associated with the onset of this disease.

Background: Natalizumab, which is efficient in preventing relapses and progression of

From these data we propose that inhibition of peripheral and intrathecal T-cell activation and suppression of CNS effector-phase migration both characterize efalizumab-associated PML. LFA-1 may be a crucial factor in homeostatic JC virus control.

EBV has been consistently associated with MS, but its signature in the CNS has rarely been examined. In this study, we assessed EBV-specific humoral and cellular immune responses in the cerebrospinal fluid (CSF) of patients with early MS, other inflammatory neurological diseases (OIND) and non-inflammatory neurological diseases (NIND). The neurotropic herpesvirus CMV served as a control. Virus-specific humoral immune responses were assessed in 123 consecutive patients and the intrathecal recruitment of virus-specific antibodies was expressed as antibody indexes. Cellular immune responses tested in the blood of 55/123 patients were positive in 46/55. The CD8 1 CTL responses of these 46 patients were assessed in the blood and CSF using a CFSE-based CTL assay. We found that viral capsid antigen and EBV-encoded nuclear antigen-1, but not CMV IgG antibody indexes, were increased in early MS as compared with OIND and NIND patients. There was also intrathecal enrichment in EBV-, but not CMV-specific, CD8 1 CTL in early MS patients. By contrast, OIND and NIND patients did not recruit EBV-nor CMV-specific CD8 1 CTL in the CSF. Our data, showing a high EBV-, but not CMV-specific intrathecal immune response, strengthen the association between EBV and MS, in particular at the onset of the disease.