[1] St Vincents Univ Hosp, Dublin 4, Ireland
[2] Cleveland Clin, Mellen Ctr Multiple Sclerosis Treatment & Res, Cleveland, OH 44106 USA
[3] Baylor Inst Immunol Res, Multiple Sclerosis Program, Dallas, TX USA
[4] UCL, Inst Neurol, NMR Res Unit, London, England
[5] Charles Univ Prague, Fac Med 1, Dept Neurol, Prague, Czech Republic
[6] Virginia Mason Med Ctr, Seattle, WA 98101 USA
[7] Biogen Idec Inc, Cambridge, MA USA