Vitamin D has a direct immunomodulatory effect on CD8+ T cells of patients with early multiple sclerosis and healthy control subjects

Little is known on a putative effect of vitamin D on CD8+ T cells. Yet, these cells are involved in the immmunopathogenesis of MS. We assessed the cytokine profile of EBV-specific CD8+ T cells of 10 early MS patients and 10 healthy control subjects with or without 1,25(OH)2D3 and found that, with 1,25(OH)2D3, these cells secreted less IFN-γ and TNF-α and more IL-5 and TGF-β. CD4+ T cell depletion or even culture with CD8+ T cells only did not abolish the immunomodulatory effect of 1,25(OH)2D3 on CD8+ T cells, suggesting that 1,25(OH)2D3 can act directly on CD8+ T cells.