1. Department of Immunobiology Yale School of Medicine New Haven Connecticut 06511 USA
2. Department of Neurology Yale School of Medicine New Haven Connecticut 06511 USA
3. Neuromuscular Division, Department of Neurology Duke University Medical Center Durham North Carolina 27710 USA
4. Department of Dermatology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania 19104 USA
5. Department of Neurology The University of North Carolina at Chapel Hill CB#7025, Houpt Building, 170 Manning Drive Chapel Hill North Carolina 27599‐7025 USA