1. Department of Pediatrics, Chung-Ang University College of Medicine, Seoul 156-861, Korea.
2. Environmental Health Center for Atopic Diseases, Samsung Medical Center, Seoul 135-710, Korea.
3. Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
4. Department of Pediatircs, Medical Research Institute, Pusan National University College of Medicine, Busan 602-739, Korea.