1. Department of Neurology, Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
2. VA Health Care System, Palo Alto, CA 94304
3. Department of Pathology, Stanford University School of Medicine, Stanford, CA 95305
4. Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215