Serum homocysteine levels in relation to clinical progression in multiple sclerosis C E Teunissen1, J Killestein2, J J Kragt2, C H Polman2, C D Dijkstra1, H J Blom3 1 Department of Molecular Cell Biology and Immunology, MS Centre Amsterdam, VU University Medical Centre Amsterdam, The Netherlands 2 Department of Neurology, MS Centre Amsterdam, VU University Medical Centre Amsterdam, The Netherlands