Expanded T lymphocytes in the cerebrospinal fluid of multiple sclerosis patients are specific for Epstein-Barr-virus-infected B cells.

Epstein-Barr virus (EBV) infection has long been associated with multiple sclerosis (MS), but the role of EBV in the pathogenesis of MS is not clear. Our hypothesis is that a major fraction of the expanded clones of T lymphocytes in the cerebrospinal fluid (CSF) are specific for autologous EBV-infected B cells. We obtained blood and CSF samples from eight relapsing-remitting patients in the process of diagnosis. We stimulated cells from the blood with autologous EBV-infected lymphoblastoid cell lines (LCL), EBV, varicella zoster virus, influenza, and candida and sorted the responding cells with flow cytometry after 6 d. We sequenced the RNA for T cell receptors (TCR) from CSF, unselected blood cells, and the antigen-specific cells. We used the TCR Vß CDR3 sequences from the antigen-specific cells to assign antigen specificity to the sequences from the CSF and blood. LCL-specific cells comprised 13.0 ± 4.3% (mean ± SD) of the total reads present in CSF and 13.3 ± 7.5% of the reads present in blood. The next most abundant antigen specificity was flu, which was 4.7 ± 1.7% of the reads in the CSF and 9.3 ± 6.6% in the blood. The prominence of LCL-specific reads was even more marked in the top 1% most abundant CSF clones with statistically significant 47% mean overlap with LCL. We conclude that LCL-specific sequences form a major portion of the TCR repertoire in both CSF and blood and that expanded clones specific for LCL are present in MS CSF. This has important implications for the pathogenesis of MS.

The concentrations of antibodies to Epstein-Barr virus decrease during ocrelizumab treatment.

BACKGROUND: Epstein-Barr Virus (EBV) is strongly associated with multiple sclerosis (MS). After initial infection, EBV maintains a life-long latent infection in B lymphocytes. Depletion of B lymphocytes from the blood with the anti-CD20 antibody ocrelizumab (OCR) markedly reduces disease activity in MS. Our objective was to measure the effect of OCR treatment on the antibody response to EBV and human antigens that are cross-reactive with EBV. METHODS: Blood was collected from MS patients before and during OCR treatment. Antibodies to three EBV antigens (EBNA-1, BFRF3, and gp350) and three human proteins that are cross-reactive with EBV (septin-9, DLST, and HNRNPL) were quantified with Western blots. Antibodies to EBNA-1 and BFRF3 were also quantified with ELISA. RESULTS: Antibodies to the EBV proteins BFRF3 and EBNA-1 measured on Western blot were significantly decreased after 12 months on OCR. Subsequent testing with ELISA confirmed the decrease for both BFRF3 and EBNA-1. With Western blots, there was a trend to decreased antibody response to septin-9 and DLST, but not HNRNPL. Total IgG concentration did not change. CONCLUSION: The antibody response to some EBV antigens decreases in OCR treated patients. The benefit of OCR for MS may be through removal of EBV antigenic stimulus.

The cellular immune response against Epstein-Barr virus decreases during ocrelizumab treatment.

BACKGROUND: Epstein-Barr Virus (EBV) is strongly associated with multiple sclerosis (MS). After initial infection, EBV maintains a life-long latent infection in B lymphocytes. Depletion of B lymphocytes from the blood with the anti-CD20 antibody ocrelizumab markedly reduces disease activity in MS. Our objective was to measure the effect of ocrelizumab treatment on the cellular immune response to EBV. METHODS: Blood was collected from MS patients before and during ocrelizumab treatment. Peripheral blood mononuclear cells were stimulated with various antigens, and the response was measured using tritiated thymidine for proliferation and ELIspot for number of interferon-γ producing cells. RESULTS: The proliferation to autologous EBV-infected cells (LCL) was decreased after both 6 and 12 months of treatment. The number of interferon-γ producing cells on ELIspot in response to stimulation with either LCL or EBV also decreased. Responses to varicella zoster virus, influenza virus, and a mitogen did not change significantly. CONCLUSION: The cellular immune response to EBV and LCL decreases during treatment with ocrelizumab. The benefit of ocrelizumab for MS may be through removal of EBV antigenic stimulus.