[1] Saga Univ, Dept Internal Med, Fac Med, Saga 840, Japan
[2] Kagoshima Univ, Grad Sch Med & Dental Sci, Dept Neurol & Geriatr, Kagoshima 890, Japan
[3] Kagoshima Univ, Grad Sch Med & Dental Sci, Ctr Chron Viral Dis, Div Mol Pathol, Kagoshima, Japan