[1] Kyoto Min Iren Cent Hosp, Kansai Multiple Sclerosis Ctr, Kyoto, Japan
[2] Juntendo Univ Hosp, Tokyo, Japan
[3] Kyushu Univ Hosp, Fukuoka 812, Japan
[4] Biogen Inc, 70 Norden Rd, Maidenhead, Berks, England
[5] Biogen Inc, 14 Cambridge Ctr, Cambridge, MA 02142 USA