Our laboratory reported that increased expression of a possible biomarker signature, consisting of TLR2, TLR4 and CCR1, in a T-subset is associated with rapid MS progression. The investigators will test whether a significant proportion of patients at baseline upregulate this biomarker signature in one or more T-subsets, whether expression of this biomarker signature changes with treatment with Gilenya and whether expression levels of this signature predict disease activity or progression over a 12 month followup period. The investigators will study patients who are already being treated with Gilenya by their neurologists or who are already being treated with Gilenya as part of a clinical trial sponsored by Novartis Pharmaceuticals Canada. Patients will not be treated with Gilenya for the purposes of our study.