1. Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
2. Department of Obstetrics and Gynecology, 3rd Xiangya Hospital, Central South University of China, Changsha, Hunan, People's Republic of China
3. Department of Pathology, 2nd Xiangya Hospital, Central South University of China, Changsha, Hunan, People's Republic of China
4. Department of Obstetrics and Gynecology, 2nd Xiangya Hospital, Central South University of China, Changsha, Hunan, People's Republic of China
5. Department of Clinical Diagnosis, 2nd Xiangya Hospital, Central South University of China, Changsha, Hunan, People's Republic of China
6. Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
7. Department of Histology and Embryology, Xiangya School of Medicine, Central South University of China, Changsha, Hunan, People's Republic of China