1. Center for AIDS Research, Kumamoto University, Kumamoto, Japan.
2. Department of AIDS Clinical Center, National Center for Global health and Medicine, Tokyo, Japan.
3. Department of Gastroenterology and Hepatology, National Center for Global Health and Medicine, Tokyo, Japan.
4. Department of Gastroenterology and Hepatology, National Center for Global Health and Medicine, Kohnodai Hospital, Chiba, Japan.