The difference of PD-L1 expression between only HPV-positive patients and premalignant cervical lesion patients did not be reported in present studies. And to test the PD-L1 expression in some cervical cell lesion studies using cervical exfoliated cells sample also was ignored. Meanwhile, the PD-L1 expression as a predictive biomarker still existed controversy. So in the study, first to compare the expression of PD-L1 between only HPV-positive patients and premalignant cervical lesion patients, then to research the association between PD-L1 and HPV status, lastly to explore the possible prognostic value for HPV treatment in premalignant cervical lesion patients.
Cervical exfoliated cells samples of 54 premalignant cervical lesion patients with HPV16 infection were collected; meanwhile the cervical exfoliated cells samples from 20 healthy women without HPV infection and 20 patients with only HPV16 infection but cervical cytology normal were collected as 2 control groups. Flow-through hybridization and gene chip (FHGC) was used to detect the HPV type, the PD-L1 expression was tested by Flow cytometry analysis, the methylation-sensitive high-resolution melting (MS-HRM) was used to test the HPV16 L1 gene methylation. The 54 premalignant cervical lesion patients were followed up in 18 months to assess the prognostic value of PD-L1 for HPV treatment.
The PD-L1 positive cell rate and mean fluorescence intensity of PD-L1 positive cell in premalignant cervical lesion patients with HPV16 infection were higher than 2 control groups. Mean fluorescence intensity of PD-L1 positive cell were increased in 54 cases when existing multiple HPV status and high HPV16-L1 gene methylation (L1 gene methylation more than 50%). High PD-L1 expression (PD-L1 positive cell rate more than 10%), high HPV16-L1 gene methylation, and multiple HPV infection status could prolong the time to clean HPV infection by Kaplan–Meier analysis. Multivariate Cox proportional hazards analysis also showed that all of high PD-L1 expression, high HPV-L1 methylation, and multiple HPV infection status should increase the risk of HPV unclearance in premalignant cervical lesion patients; the hazard ratio (HR) was 2.043 (CI: 1.050–3.973), 2.797 (CI: 1.277–6.122), and 3.050 (CI: 1.406–6.615).
PD-L1 expression only was correction with HPV infection when the infection induced the cervical cells to create the lesion. PD-L1 was the risk factor of HPV unclearance in premalignant cervical lesion patients, so anti-PD-L1 therapy could be a potential effectiveness way of HPV infection in premalignant cervical lesion patients.