[1] Nagoya Univ, Sch Med, Virol Lab, Res Inst Dis Metab & Control, Nagoya, Aichi 4668550, Japan
[2] Fujita Hlth Univ, Sch Med, Dept Pediat, Toyoake, Aichi 4701192, Japan
[3] Nagoya Univ, Sch Med, Dept Pediat, Nagoya, Aichi 466, Japan
[4] Japanese Red Cross Nagoya First Hosp, Childrens Med Ctr, Div Hematol Oncol, Nagoya, Aichi 4530046, Japan