1. Department of Allergy & Rheumatology, Ajou University School of Medicine, Suwon, Korea.
2. Department of Internal Medicine, Inha University College of Medicine, Incheon, Korea.
3. Division of Allergy & Respiratory Medicine, Soonchunhyang University Hospital, Bucheon, Korea.
4. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.