1. Department of Pediatrics, Chang Gung Memorial Hospital, Keelung 204, Taiwan
2. College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
3. Division of Allergy, Asthma and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
4. Division of Chest, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
5. Department of Pediatrics, Municipal TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City 236, Taiwan