1. Department of Medical Sciences, Neurology, Uppsala University , Uppsala SE-751 85 , Sweden
2. Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital , Stockholm SE-171 77 , Sweden
3. Department of Cell and Molecular Biology, Uppsala University , Uppsala SE-751 23 , Sweden
4. Department of Immunology, Genetics and Pathology, Uppsala University , Uppsala SE-751 85 , Sweden
5. Department of Medical Sciences, Clinical Chemistry, Uppsala University , Uppsala SE-751 85 , Sweden