CD4 and relapsing-remitting multiple sclerosis: The expression levels of miR-126 and miR-17 resulted downregulated in CD4+ T cells of RRMS patients under treatment with Natalizumab, while they were upregulated during the clinical relapse, suggesting that the therapeutic effect of Natalizumab may be mediated by these two miRNAs possibly implicated in the pathogenesis of MS [86,87].