1. Department of Immunology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, P. R. China
2. Department of Gynecology and Obstetrics, Jinan Central Hospital affiliated to Shandong University, Jinan, Shandong, P. R. China
3. Department of Gynecology and Obstetrics, Clinical Medical School, Shandong University, Jinan, Shandong, P. R. China