1 Department of Neurology (A.R.R., S.S.Z., J.M.G.) and Program in Immunology (S.S.Z.), University of California San Francisco; Department of Neurology (R.P.L.), Wayne State University, Detroit, MI; Partner's Neurology Training Program (E.M.); MGH and Brigham and Women's Hospitals, Harvard Medical School, Boston, MA; and E.M. is now with the Department of Neurology, Dell Medical School at the University of Texas at Austin; Central Texas Neurology Consultants (E.J.F.), and Department of Neurology, Dell Medical School at the University of Texas at Austin; Department of Neurology (E.M., A.L.), and Department of Neurology and Ophthalmology (T.C.F., E.F), Dell Medical School at the University of Texas at Austin; Department of Neurology (L.F.), University of Texas at Houston; and the National Multiple Sclerosis Society, New York, NY.