Humoral response to Epstein-Barr virus in patients with multiple sclerosis treated with B cell depletion therapy.

BACKGROUND: B cell depletion therapy is highly effective in relapsing-remitting multiple sclerosis (RRMS). However, the precise underlying mechanisms of action for its biological effects in MS have still not been clarified. Epstein-Barr virus (EBV) is a known risk factor for MS and seems to be a prerequisite for disease development. EBV resides latently in the memory B cells, and may not only increase the risk of developing MS, but also contribute to disease activity and disability progression. Therefore, the effects of B cell depletion in MS could be associated with the depletion of EBV-infected cells and the altered immune response to the virus. In this study, we investigate the impact of B cell depletion on the humoral immune response specific to EBV in patients with MS. METHODS: Newly diagnosed, treatment-naïve patients with RRMS were followed up to 18 months after initiation of B-cell depletion therapy in the Overlord-MS study, a phase III trial (NCT04578639). We analyzed serum sampled before treatment and after 3, 6, 12 and 18 months for immunoglobulin γ (IgG) against Epstein-Barr nuclear antigen 1 (EBNA1) and Epstein-Barr viral capsid antigen (VCA). We analyzed antibodies to cytomegalovirus (CMV) and total IgG in serum, as controls for viral and overall humoral immunity. The risk allele, HLA-DRB1*15:01, and the protective allele, HLA-A*02:01, were determined in all participants. In addition, polymerase chain reaction (PCR) for circulating EBV-DNA was performed in the first 156 samples drawn. The associations between time on B cell-depletion therapy and serum anti-EBV antibody levels were estimated using linear mixed-effects models. RESULTS: A total of 290 serum samples from 99 patients were available for analysis. After 6, 12 and 18 months, the EBNA1 IgG levels decreased by 12.7 % (95 % CI -18.8 to -6.60, p < 0.001), 12.1 % (95 % CI -19.8 to -3.7, p = 0.006) and 14.6 % (95 % CI to -25.3 to -2.4, p = 0.02) respectively, compared to baseline level. Carriers of the HLA-DRB1*15:01 allele had higher EBNA1 IgG levels at baseline (p = 0.02). The VCA IgG levels significantly increased by 13.7 % (95 % CI 9.4 to 18.1, p < 0.001) after 3 months, compared to baseline, and persisted at this level throughout the follow-up. CMV IgG levels decreased, but to a lesser extent than the decrease of EBNA1 IgG, and total IgG levels decreased during therapy. Circulating EBV-DNA was found in only three of 156 samples from 64 patients. CONCLUSIONS: EBNA1 IgG levels decreased, while VCA IgG levels increased, during B cell depletion therapy. This supports the hypothesis that the mechanism of action for B cell depletion therapy might be mediated by effects on EBV infection, which, in turn, mitigate immune cross-reactivity and disease perpetuation.

Interferon ß1a treatment does not influence serum Epstein-Barr virus antibodies in patients with multiple sclerosis.

There is increasing evidence of Epstein-Barr virus (EBV) being conditional in multiple sclerosis (MS) pathogenesis and influential for disease activity. Interferon-beta (IFNß) is a cytokine with antiviral effects used to treat MS, in which a possible antiviral effect against EBV has been questioned. In this study, we investigated the effect of IFNß-1a treatment on serum EBV antibody levels in 84 patients with relapsing-remitting MS. In the 18 months following IFNß-1a treatment initiation, there were no significant associations between treatment and serum levels of Epstein-Barr nuclear antigen 1 (EBNA-1) immunoglobulin (Ig) G, early antigen (EA) IgG, viral capsid antigen (VCA) IgG or VCA IgM. The findings suggest that IFNß-1a treatment does not influence the humoral response to EBV in patients with MS.

Breastfeeding and treatment for multiple sclerosis. / Amming og behandling av multippel sklerose.

Monoclonal antibody therapy is effective for multiple sclerosis, and only small amounts of antibodies are transferred to breast milk. Even though the approved product descriptions advise against breastfeeding during medicinal treatment, several of the most effective MS drugs are compatible with breastfeeding.

Safety of breast feeding during rituximab treatment in multiple sclerosis.

BACKGROUND: There are limited data on the safety of breast feeding during rituximab therapy. Our objective is to determine exposure from breast feeding and biological effects of rituximab in breastfed infants. METHODS: In our case series of six mother-infant pairs, the nursing mothers with relapsing-remitting multiple sclerosis received rituximab during breast feeding. As part of clinical follow-up, six serial breast milk samples, and blood samples from both mothers and infants, were collected and analysed. RESULTS: The median average rituximab concentration (Cavg) in breast milk was 0.04 µg/mL and the estimated relative infant dose (RID) was 0.07%. The highest measured concentration of rituximab in the breast milk samples was 0.25 µg/mL, giving an estimated RID of 0.26%.All infant serum rituximab concentrations were below 0.01 µg/mL. The CD19 +B cell count values were within the 10th- 90th percentiles of reported normal ranges in healthy infants. CONCLUSIONS: We found minimal transfer of rituximab into breast milk and could not reliably detect levels of rituximab in infant serum. B cell counts in infants were unaffected.