1. Division of Respiratory Diseases, Department of Medicine; Kawasaki Medical School; Kurashiki Okayama 701-0192 Japan
2. Department of Infectious Diseases; Institute of Medical Science, The University of Tokyo; Minato-ku Tokyo 108-8639 Japan
3. Fourth Department of Medicine; International Medical Center of Japan; Shinjuku-ku Tokyo 162-0052 Japan
4. Division of Clinical Laboratory Medicine; Yokohama City University Hospital; Yokohama Kanagawa 236-0004 Japan
5. Second Department of Internal Medicine; Nagasaki University; Nagasaki Nagasaki 852-8523 Japan