The Role of T Lymphocyte Subsets in The Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system (CNS). Although, the contribution of various cells such as B cells, CD8 T cells, microglia/macrophages, dendritic cells, asterocytes and mast cells in the pathogenesis of MS have been demonstrated, however, it seems that autoreactive myelin specific CD4 T cells play a central role in pathological events contributing in MS pathogenesis. The aim was to evaluate the recent findings regarding the properties of T lymphocyte subsets and their roles in pathogenesis of MS disease. Functionally, distinct effector T cells are induced from naïve T cells upon antigenic stimulation, including Th1, Th2, Th17, Th22, Th9, and regulatory T (Treg) cells which are characterized based on their cytokine patterns. Of the activated T cells, Th1 cells secreting IFN-γ, Th17 cells producing IL-17, Th9 releasing IL-9, and Th22 secreting IL-22 play major roles in MS development, while Th2 cells producing IL-4, and Treg cells secreting IL-10 and TGF-β have been associated with a reduction of CNS inflammation and improvement of MS. The modulation of Th1, Th17, Th9 and Th22 cells activity and the promotion of Th2 and Treg cell-related responses can be more consider for immunological treatment of MS disease.