1. Department of Medicine and University of Toronto, Toronto, Ontario, Canada.
2. Department of Neurology, University of Toronto, Toronto, Ontario, Canada.
3. Department of Internal Medicine and Cedars-Sinai Medical Center, Los Angeles, California, USA.
4. Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA.
5. Department of Neurology and Rush University Medical Center, Chicago, Illinois, USA.
6. Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois, USA.
7. Division of Neuroimmunology, Department of Neurology, Columbia University Irving Medical Center, New York, New York, USA.
8. Department of Neurological Sciences, Larner College of Medicine at the University of Vermont, Burlington, Vermont, USA.
9. Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA.
10. Department of Internal Medicine and Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
11. Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.