[1] Natl Utano Hosp, Dept Neurol, Ukyo Ku, Kyoto 616, Japan
[2] Natl Utano Hosp, Clin Res Ctr, Ukyo Ku, Kyoto 616, Japan
[3] Kyoto Red Cross Blood Ctr, Kyoto, Japan
[4] Kyoto Microbiol Inst, Kyoto, Japan
[5] Kobe City Gen Hosp, Publ Hlth Res Inst, Dept Pediat, Kobe, Hyogo, Japan
[6] Hiroshima Univ, Sch Med, Dept Internal Med 3, Hiroshima, Japan
[7] Kyoto Univ, Inst Virus Res, Kyoto 606, Japan