IFNβ-1a therapy for multiple sclerosis expands regulatory CD8+ T cells and decreases memory CD8+ subset: A longitudinal 1-year study

The beneficial effects of interferon beta-1a (IFN beta-1a) in multiple sclerosis (MS) remain only partially understood. CD8(+) T cells are key cells in MS pathogenesis that contribute to axonal damage in MS, whereas CD4(+) regulatory T cells (T-Reg) and CD8(+) regulatory/suppressor T cells (Ts) play an important role in protecting against subsequent MS activity. We analysed ex vivo changes on T-Reg and on the different subsets of CD4(+) and CD8(+) T Lymphocytes, before IFN beta-1a (Rebif) therapy and at 3, 6, and 12 months after treatment, in 23 MS patients and in 26 healthy controls. IFN beta-1a significantly increased the proportions of CD4(+) T-Reg and regulatory CD8(+) T cells (Tr). Memory CD8(+) T cells were significantly decreased after 1 year of treatment, maybe reflecting down-regulation of abnormally persistent systemic activation in MS patients. After 1 year of IFN beta-1a, a direct correlation was observed between plasmacytoid dendritic cells and effector CD8(+) T cells. (C) 2009 Elsevier Inc. All rights reserved.