Human papillomavirus (HPV) infection has become one of the most important health problems faced by women all over the world. A large number of studies have shown that women's cervical, vaginal and perianal precancerous lesions, related cancers, condyloma acuminatum and other sexually transmitted diseases (STD) are closely related to HPV infection. Among them, the persistent infection of high-risk human papillomavirus (HR-HPV) is closely related to the occurrence of invasive cervical cancer. Previous studies have shown that there are significant differences in the effects of multiple HPV infection and persistent infection of different types (such as type-16, -18, -39 and -52) on different levels of cervical lesions, and there is a certain correlation between HPV load in the process of persistent infection and the degree of cervical lesions. In addition, other studies have shown that HPV-16 viral load has certain clinical significance in predicting Cin2 / CIN3 high-grade cervical lesions, and HPV viral load level is significantly different in cervical low-grade squamous intraepithelial lesion (LSIL) and cervical high-grade squamous intraepithelial lesion (HSIL). The above biological changes such as HPV infection type, quantity and proportion can promote the occurrence and development of cervical precancerous lesions and related cancers to varying degrees. It can be seen that the study of the relationship between HPV viral load and cervical lesions is of great significance for clinical disease development prediction and cervical cancer screening.

Based on our previous studies and clinical practice, this study carried out a multi center cohort study in Fujian Province, China. In this study, six research including Fujian Maternity and Child Health Hospital, Mindong Hospital of Ningde City, Zhangzhou affiliated Hospital of Fujian Medical University, Quanzhou First Hospital Afflicated to Fujian Medical University, Xiamen Maternity and Child Health Hospital Affiliated to Xiamen University and Ningde Municipal Hospital of Ningde Normal University were included, each of which included 500 individuals, with a total of 3000 women with low-grade squamous intraepithelial lesion were enrolled. For the first time, the researchers will collect 2 samples of cervical exfoliated cells (one of which will be sub packed into 3) and 4 samples of vaginal fornix swabs from subjects, then at the 6th, 12th and 24th months after the first sampling, the subjects need to return to the hospital, collect 2 samples of cervical exfoliated cells (one of which will be sub packed) and 4 samples of vaginal fornix swabs again in order to observe and record the development of the disease. During this process, if abnormal cervical lesions are found, the subjects will be biopsied under colposcopy according to relevant guidelines. Samples from cervix would be sent for PCR-sequencing, HPV tests and Thinprep cytologic test (TCT). And samples from vaginal fornix would be sent for sequencing and bioinformatic analysis. A prospective cohort study was conducted to explore the correlation between the characteristics, progression and prognosis of female genital tract lesions and HPV infection type, load and vaginal microenvironment.

Inclusion Criteria:

• Women aged 20 and over.
• The result of cervical histopathology in the last 3 months was low-grade squamous intraepithelial lesion (LSIL).
• Non pregnant people with sexual history.
• Asexual life, no vaginal medication or flushing before 72 hours of sampling.

Exclusion Criteria:

• Within 8 weeks after pregnancy or postpartum.
• Patients with history of genital tract tumor.
• History of HPV vaccination.
• Previous history of hysterectomy, cervical surgery, pelvic radiotherapy Historical.
• In recent one month, she has received genital tract infection, HPV or other STDs treatment related to the infection of mycoplasma.
• Use antibiotics or vaginal microecological improvement products in recent 1 month.

Chinese women aged 20 and over with low-grade squamous intraepithelial lesion in results of cervical histopathology.