1. Department of Allergy and Clinical Immunology, Hanoi Medical University, Hanoi 10000, Vietnam.
2. Center of Allergology and Clinical Immunology, Bach Mai Hospital, Hanoi 844, Vietnam.
3. Department of Allergy and Clinical Immunology, Royal North Shore Hospital and Sydney Medical School-Northern, The University of Sydney, Sydney, NSW 2065, Australia.
4. Outpatients Department, Bach Mai Hospital, Hanoi 844, Vietnam.
5. Section of Allergy, Asthma and Immunology, Penn State University, Hershey, PA 17033, USA.
6. Sonic Clinical Institute, Macquarie Park, Sydney, NSW 2113, Australia.