Analysis of Lymphocyte Cell Surface Adhesion Marker Expression in Natalizumab Population With Active Control

Patients at various timepoints in their MS treatment or who are beginning certain MS treatments will be consented and have blood specimens collected to allow for an immunological comparison. The decision to treat with disease modifying therapies is made independently from this observational study. Primary endpoint: To further understand the delineation of lymphocyte cell adhesion marker down regulation within a treatment naïve patient population and at various stages of treatment. Secondary endpoint: To understand the correlation between natalizumab pharmacodynamics, pharmacokinetics and lymphocyte cell adhesion marker down regulation. The results of various biomarkers and immunological testing (including CD62L, LFA-1, sCD62L, sLFA-1, sVCAM, VLA-4 saturation, IgG4, CBC with absolute differential) will be compared amongst the groups consented. The treatment naive group will be compared longitudinally.