1. From the Harvard Medical School (M.S.S., T.C.); Department of Neurology (M.S.S., T.C.), Brigham and Women's Hospital, Boston, MA; Department of Neurology (D.E.H., J.C.M.), Johns Hopkins University School of Medicine, Baltimore, MD; Department of Neurology and Program in Immunology (S.S.Z.), University of California at San Francisco; Department of Neurology (M.D.G.), Virginia Commonwealth University, Richmond; and Department of Neurology (C.R.), Columbia University, New York.