1. Department of Respiratory Medicine, Tohoku University School of Medicine, Sendai 980-8574, Japan
2. Division of Respiratory Diseases, Department of Internal Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan
3. Department of Clinical Application, Translational Research Center, Tohoku University, Sendai 980-8574, Japan
4. Department of Advanced Preventive Medicine for Infectious Disease, Tohoku University School of Medicine, Sendai 980-8574, Japan