1. Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
2. Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
3. King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
4. Clinical Microbiology-Immunology Laboratories, University of North Carolina Health Care, Chapel Hill, North Carolina, USA
5. Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA