1 Department of Neuroimmunology, Institute for Multiple Sclerosis Research, The Hertie Foundation, Göttingen, Germany; Max Planck Institute for Experimental Medicine, University of Göttingen Medical School, Göttingen, Germany.
2 Department of Neurology, St Josef-Hospital, Ruhr-University Bochum, Bochum 44791, Germany. Electronic address: ralf.gold@ruhr-uni-bochum.de.