Several sphingosine 1-phosphate (S1P1) receptor antagonists, such as fingolimod (FTY720), have been commonly used for the treatment of RRMS; these antagonists selectively retain CCR7+ naïve T cells and TCM, and particularly autoreactive Th17 cells, within the secondary lymphoid organs (24–26). Here, CCR7 is linked to relapsing-remitting multiple sclerosis.