1. Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
2. Department of Internal Medicine, Sano Kousei General Hospital, Sano, Tochigi, Japan
3. Department of Respiratory Medicine, National Hospital Organization Tokyo Medical Center, Meguro, Tokyo, Japan
4. Department of Respiratory Medicine, Saitama Medical University, Iruma-gun, Saitama, Japan
5. Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara-shi, Kanagawa, Japan