1 Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan. hoyohoyo18@hotmail.com.
2 Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
3 Laboratory of Viral Infection, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan.