1 Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, 162-8655 Tokyo, Japan.
2 Division of Rheumatic Diseases, National Center for Global Health and Medicine, 1-21-1, Toyama, Shinjuku-ku, 162-8655 Tokyo, Japan. Electronic address: hiroyuki_yjp2005@yahoo.co.jp.