1. Department of Pediatrics, Chang Gung Memorial Hospital, Keelung Branch, Keelung 204, Taiwan
2. College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
3. Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan
4. Division of Pediatric Pulmonology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan