1. Department of Pulmonary, Allergy, and Critical Care Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
2. Allergy and Clinical Immunology Research Center, Hallym University College of Medicine, Chuncheon, Korea.
3. Department of Statistics, Clinical Trial Center, Ajou University Medical Center, Suwon, Korea.
4. Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.