FTY720, an agonist of sphingosine 1-phosphate receptor (SIPR) and a substrate for sphingosine kinase (SphK), is an immunomodulatory drug used for oral treatment of relapsing-remitting multiple sclerosis (RRMS) (Huwiler and Zangemeister-Wittke, 2018), which has little interference with immune response to infection (Pinschewer et al., 2000). This evidence concerns the gene S1PR1 and relapsing-remitting multiple sclerosis.