1. Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania.
2. Nanning Center for Disease Control and Prevention, Nanning, Guangxi, People's Republic of China.
3. Guangxi Key Laboratory of AIDS Prevention and Treatment, School of Public Health, Guangxi Medical University, Nanning, People's Republic of China.
4. Center for AIDS Research, the Affiliated Ruikang Hospital of Guangxi University of Chinese Medicine, Nanning, People's Republic of China.