1. Department of Infectious Diseases, Internal Medicine, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
2. Department of Otolaryngology, Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
3. Laboratory Medicine, Department of Infectious Diseases, Kanazawa University, Kanazawa 920-8641, Ishikawa, Japan
4. Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan