Division of Allergy, Asthma and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan. College of Medicine, Chang Gung University, Taoyuan 333, Taiwan. Department of Nephrology, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan. Division of Allergy, Immunology and Rheumatology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 333, Taiwan. Department of Pediatrics, New Taipei Municipal TuCheng Hospital, New Taipei City 236, Taiwan. National Defense Medical Center, Graduate Institute of Medical Science, Taipei 114, Taiwan.