1. Department of Internal Medicine, Division of Respiratory Medicine, Jikei University School of Medicine, Kashiwa Hospital, 163-1 Kashiwashita, Kashiwa, Chiba 277-8567, Japan
2. Division of Diagnostic Pathology, Jikei University School of Medicine, Kashiwa Hospital, Chiba, Japan
3. Department of Internal Medicine, Division of Respiratory Medicine, Jikei University School of Medicine, Tokyo, Japan