[1] Kumamoto Reg Med Ctr, Dept Pediat, Kumamoto, Kumamoto 8600811, Japan
[2] Kumamoto Univ, Dept Pediat, Grad Sch Med Sci, Kumamoto, Japan
[3] Kumamoto Med Ctr, Dept Pediat, Natl Hosp Org, Kumamoto, Japan
[4] Vaccinat Ctr Kumamoto Prefecture, Kumamoto, Japan
[5] Miyazaki Univ, Dept Reprod & Dev Med, Div Pediat, Fac Med, Miyazaki, Japan
[6] Kazusa DNA Res Inst, Dev Technol Dept, Kisarazu, Chiba, Japan
[7] Kyushu Univ, Dept Perinatal & Pediat Med, Grad Sch Med Sci, Fukuoka 812, Japan