The beneficial effects of vitamin D3 on reducing antibody titers against Epstein–Barr virus in multiple sclerosis patients

•We examined the effect of vitamin D3 on EBV titers in MS patients.•Forty MS patients were randomized to 2 groups: vitamin D3 treated and control group.•All MS patients were seropositive for EBV.•Increasing EBV titers were observed in almost all patients after 6 months.•Increasing levels in the treatment group was significantly less than control group.

Recently, the relationship between immunoreactivity to Epstein–Barr virus (EBV) and hypo-vitamin D in multiple sclerosis (MS) patients has been described. The aim of this study was to investigate whether vitamin D3 supplementation in MS patients could influence the immune response against latent EBV infection. Forty MS patients were recruited in this study. Twenty-seven patients were supplemented with 50,000 IU/week of vitamin D3 for 6 months and thirteen enrolled as controls. 25-Hydroxyvitamin D (25OHD) levels and IgG titers against EBNA1 and VCA were determined pre- and post-supplementation. All the patients were seropositive for EBV prior to vitamin D supplementation. In this cohort, 22.5% and 47.5% of the MS patients had deficient and insufficient levels of 25OHD, respectively. Our findings confirm that antibody titers against EBV in MS patients rise after the onset of the disease and indicate that vitamin D3 supplementation could limit augmentation of these titers in MS patients.