1. Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, Hongo, Bunkyo‐ku, Tokyo,
2. Department of Medicine, Juntendo University Izu‐Nagaoka Hospital, Nagaoka, Izu‐Nagaoka‐cho, Tagata‐gun, Shizuoka,
3. Ajinomoto Co., Inc., Kyobashi, Chuo‐ku, Tokyo,
4. Department of Microbiology, Tokyo Medical and Dental University School of Medicine, Yushima, Bunkyo‐ku, Tokyo, Japan