[1] Saitama Childrens Med Ctr, Dept Hematol Oncol, Saitama, Japan
[2] Saitama Childrens Med Ctr, Dept Pathol, Saitama, Japan
[3] Kyoto Univ Hosp, Dept Pediat, Kyoto 606, Japan
[4] Tokyo Metropolitan Kiyose Childrens Hosp, Div Diagnost Pathol, Dept Lab Med, Tokyo, Japan