[1] Hokkaido Univ, Grad Sch Med, Dept Pediat, Kita Ku, Sapporo, Hokkaido, Japan
[2] Hokkaido Univ, Dept Oral Pathobiol Sci, Grad Sch Dent Med, Sapporo, Hokkaido, Japan
[3] Aichi Med Univ, Dept Pathol 2, Nagakute, Aichi 48011, Japan
[4] Fukuoka Univ, Sch Med, Dept Pathol, Fukuoka 81401, Japan
[5] Hokkaido Univ, Grad Sch Dent Med, Dept Oral Pathol, Sapporo, Hokkaido, Japan
[6] Gifu Univ, Dept Pathol 2, Sch Med, Gifu, Japan
[7] Kitami Red Cross Gen Hosp, Dept Pediat, Kitami, Hokkaido, Japan